Driver Controls and Instruments

Instruments and Controls Identification

Figure 3.1 represents a typical Freightliner dash equipped with all of the standard and many of the optional instruments and controls for left-hand-drive (LH DR) vehicles equipped with electronic engines. Figure 3.2 shows the Level I ICU gauge portion of the dash for those vehicles.

1. Headlight Switch
2. Panel Light Dimmer Switch
3. Cruise Control Switch, Optional
4. Cruise Control Set/Resume Switch, Optional
5. Windshield Wiper Switch
6. Windshield Washer Switch
7. Road Light Switch
8. Utility Light Switch, Optional
9. Engine Shutdown Override/Check Switch, Optional
10. Ignition Switch
11. Mirror Heat Switch, Optional
12. Level I ICU Gauges and Warning Lights
13. Marker Lights Interrupt Switch
14. Parking Brake Control Valve
15. Trailer Air Supply Valve

Fig. 3.1, Instrument and Control Panel Layout (typical, left-hand-drive vehicles)

1. Transmission Temperature Gauge, Optional
2. Coolant Temperature Gauge
3. Engine Oil Pressure Gauge
4. Dash Message Center
5. Fuel Gauge
6. Primary Air Pressure Gauge
7. Mode/Reset Push Button, Optional
8. Secondary Air Pressure Gauge
9. Speedometer
10. Tachometer, Optional

Fig. 3.2, Level I ICU Gauge Layout (typical)

Figure 3.3 represents the gauge portion of a typical right-hand-drive (RH DR) vehicle, or a vehicle with a mechanical engine.

NOTE: Right-hand-drive vehicles are built with the instrument control panel on the right side of the dash. The instrument configurations and control instructions in this manual are for left-hand-drive vehicles. In addition, dash gauges in right-hand-drive vehicles feature metric units of measure.

1. Voltmeter, Optional
2. Coolant Temperature Gauge
3. Engine Oil Pressure Gauge
4. Tachometer, Optional
5. Speedometer
6. Fuel Gauge
7. Primary Air Pressure Gauge
8. Secondary Air Pressure Gauge
9. Warning and Indicator Lights

Fig. 3.3, Gauges and Warning Lights (right-hand-drive and mechanical engine vehicles)

Controls

Ignition Switch and Key

The ignition switch can be turned to four positions: off, accessory, on, and start. See Fig. 3.4 . The ignition switch key also locks and unlocks the cab doors.

Fig. 3.4, Ignition (switch locations typical)

The key can be inserted and removed only from the off position (key slot is vertical). The headlights (low beam only), brake lights, road lights, dome lights, clearance lights, turn signals, hazard warning lights, parking lights, and the cigarette lighter operate with the ignition switch off, regardless of whether or not the key is inserted.

In the accessory position (key is turned counterclockwise), the wipers, heated mirrors, backup lamps, radio, ether start system, and all electric gauges operate.

Turn the key fully clockwise to the start position only when starting the engine. When the engine starts, release the key. When released, the key will move to the on position.

In the on position (key turned 45 degrees clockwise), all electrical systems are operable. Warning lights and buzzer for low air pressure and low oil pressure operate until the engine is started and minimum pressures are built up.

Mirror Heat Switch, Optional

One or both outside door mirrors can be heated to keep them defrosted. See Fig. 3.5 .

Fig. 3.5, Mirror Heat Switch, Optional

Panel Light Dimmer Switch

The panel lights are turned on by the headlight switch. The panel light rheostat controls the brightness of the instrument panel lights. Slide the control lever up to brighten the lights and down to dim them. Move the control lever all the way down to turn them off. See Fig. 3.6 .

Fig. 3.6, Panel Light Control Lever

Road Light Switch, Optional

The road light switch operates the road lights which are recessed into the front bumper. See Fig. 3.7 .

Fig. 3.7, Road Light Switch, Optional

For vehicles built to operate in the United States, the low-beam headlights must be turned on before the road lights can be turned on. The road lights won't go on if the high-beam headlights are already on, and switching from low beams to high beams will switch off the road lights.

For vehicles built to operate in Canada, the taillights and clearance lights must be on before the road lights can be turned on. The road light switch will not turn on the road lights unless the headlight switch is all the way up (headlights, taillights, clearance lights, marker lights, and panel lights on) or down (taillights, clearance lights, marker lights, and panel lights on).

Utility Light Switch, Optional

The utility lights, mounted in the back of the cab, are operated by the utility light switch. See Fig. 3.8 .

Fig. 3.8, Utility Light Switch, Optional

Headlight Switch and Daytime Running Lights

See Fig. 3.9 . The up position turns on the headlights, marker lights, taillights, clearance lights, and panel lights. The middle position turns on the taillights, marker lights, clearance lights, and panel lights. The down position turns all of these lights off.

Fig. 3.9, Headlight Switch

The high-beam headlights are activated by pulling up on the turn signal lever. When the headlights are on high beam, a blue light illuminates between the speedometer and tachometer. The ignition switch must be on for the high beams to operate.

Daytime running lights (DRL) are required in Canada, and optional in the United States. On vehicles equipped with DRL, turning on the ignition switch and releasing the parking brakes automatically activates the headlight low beams at 86 percent of full voltage. Turning on the regular headlights will override the DRL. While the vehicle is being operated, either the headlights or the DRL must be activated. The DRL continue to operate until the parking brakes are applied or the ignition switch is turned off.

Windshield Wipers

There are two different windshield wiper installations, one with and one without the intermittent function. On vehicles without intermittent wipers, the windshield wipers and washers are operated by separate rocker switches. To operate the wipers, move the rocker switch to one of two speed settings: low or high. See Fig. 3.10 .

1. Wiper Rocker Switch
2. Washer Rocker Switch

Fig. 3.10, Wiper and Washer Switch Locations (typical), Without Intermittent Wiper Function

On vehicles with intermittent wipers, the wiper and washer controls consist of either a rocker switch and a slider switch, or a double-paddle switch.

On vehicles with intermittent wipers with rocker switch and slider switch controls, the continuous low and high wiper speeds are engaged with the rocker switch. The intermittent wipers are turned on by moving the slider switch up to select the desired delay interval between 2 and 10 seconds. An indicator light illuminates when the slider switch is engaged. Intermittent wiper action is overridden when the rocker switch is set to either continuous position. See Fig. 3.11 .

1. Wiper Rocker Switch
2. Intermittent Wiper/Washer Slider Switch
3. Intermittent Wiper Indicator Light

Fig. 3.11, Rocker Switch and Slider Switch Locations, With Intermittent Wiper Function

On vehicles with intermittent wipers with a double-paddle switch, the top paddle, when pushed in, turns the wipers on or off. When it is pushed up, the top paddle switches the wipers to high speed; when it is pushed down, the wipers operate at low speed. See Fig. 3.12 .

1. Windshield Wiper/Washer Switch

Fig. 3.12, Double-Paddle Switch Location, With Intermittent Wiper Function

Pushing the bottom paddle up or down controls the intermittent wipers. When the bottom paddle is pushed up, the wipers operate in fast delay. When the bottom paddle is pushed down, the wipers operate in slow delay. With the wipers in delay mode (fast or slow), push the bottom paddle up to shorten the delay period, or push the paddle down to lengthen it.

Do not move the wiper arms manually. Wiper motor damage will occur if the arms are moved.

Windshield Washer

On vehicles without intermittent wipers, depress the washer rocker switch to operate the washer. Washer fluid will be sprayed onto the windshield as long as the switch is depressed. See Fig. 3.10 .

On vehicles with intermittent wipers with rocker switch and slider switch controls, push the slider switch all the way up to operate the windshield washer. See Fig. 3.11 .

On vehicles with intermittent wipers with a double-paddle switch, push in the bottom paddle to turn the washers on. When pushed in for less than 1/2-second, the wipers will perform a single, low speed dry wipe (mist function). When pushed and held in, the wash cycle begins and continues for three wiper blade cycles, or until the paddle is released. See Fig. 3.12 .

Interrupt Switch, Optional

A spring-loaded interrupt switch operates the marker lights and taillights. With the vehicle lights on, depress and release the interrupt switch to briefly turn off the marker lights and taillights. See Fig. 3.13 .

Fig. 3.13, Interrupt Switch, Optional

Caterpillar Electronic Engine Operator Control

Caterpillar electronic engines use a computer (electronic control module) to automatically control engine timing and fuel injection. The electronic features of these engines include an electronic governor, fuel-to-air ratio control, programmable engine ratings, injection timing control, fault analysis and recording, and a data link used for programming the electronic control module and troubleshooting the system.

All Caterpillar electronic engines have a check engine indicator in the lightbar located below the speedometer and tachometer. This indicator light illuminates or flashes if the engine oil pressure is low, the coolant temperature is high, the intake manifold air temperature is high, the coolant is low (optional), or whenever there is a problem within the electronic engine system. Some vehicles equipped with Caterpillar electronic engines have an automatic engine shutdown option. This option will shut off fuel to the engine if potentially damaging conditions are detected. See the Caterpillar electronic engine troubleshooting manual for troubleshooting procedures.

The cruise control and PTO governor options are controlled in two ways:

The CRUISE ON and SET/RESUME switches on the instrument control panel . See Fig. 3.14 . The CRUISE ON switch turns on the cruise control, and the SET/RESUME switch is used to select the cruise speed, or to resume cruise control after slowing down. For PTO operation, the CRUISE ON switch turns on the PTO, and the SET/RESUME switch is used to either select or resume the engine operating speed. The dash-mounted cruise control switches are also used to check the electronic control module (ECM) for system faults when the engine is not running. The SET/RESUME switch is spring-loaded to return to neutral. See Chapter 4 for complete instructions.

1. Cruise Control On/Off Switch
2. Cruise Control Set/Resume Switch
3. Engine Shutdown Override/Check Switch

Fig. 3.14, Cruise Control Switches and Engine Shutdown Override/Check Switch Locations (typical)

The optional PAUSE, RESUME, and SET buttons on the transmission shift knob . See Fig. 3.15 . The PAUSE button allows the driver to temporarily interrupt cruise control. The RESUME button allows the driver to resume the cruise speed after slowing down. The SET button allows the driver to select the cruise speed. For PTO operation, the PAUSE button temporarily interrupts PTO operation, the RESUME button resumes PTO operation at the previously selected engine speed, and the SET button is used to select the engine operating speed. See Chapter 4 for complete instructions.

Fig. 3.15, Cruise Control, Transmission Shift Knob Buttons

Cummins Electronic Engine Operator Control

The Cummins CELECT is a fuel control system installed on M11 engines. The CELECT system is controlled by a microprocessor-based computer. This computer controls specific engine and vehicle speed modes of operation to maximize vehicle fuel economy and performance.

Vehicles with CELECT engines have a yellow check engine indicator light and a red stop engine warning light in the lightbar located below the speedometer and tachometer. With the ignition switch on, both lights come on for about two seconds, then, if there is no problem with the CELECT engine system, the lights will go out. Whenever there is a problem within the electronic engine system, one of the lights will come on and stay on as long as the problem exists.

If the yellow check engine light illuminates while driving some CELECT features will not work, but the vehicle can still be driven. If the red stop engine light illuminates while driving and if the engine will not accelerate, pull off of the road and shut down the engine. In either situation, have the problem repaired as soon as possible.

If the system is programmed to shut down, the engine will shut down 30 seconds after the red engine protection light illuminates. The ignition switch will restart the engine after shutdown. However, if the potentially damaging problem still exists, the engine will operate at the reduced speed or torque level allowed just prior to shutdown.

The cruise control and PTO governor options are controlled in two ways:

The CRUISE ON and SET/RESUME switches on the instrument control panel . See Fig. 3.14 . The CRUISE ON switch turns on the cruise control, and the SET/RESUME switch is used to select the cruise speed, or to resume cruise control after slowing down. For PTO operation, the CRUISE ON switch turns on the PTO, and the SET/RESUME switch is used to either select or resume the engine operating speed. The SET/RESUME switch is spring-loaded to return to neutral. See Chapter 4 for complete instructions.

Detroit Diesel Electronic Engine Control (DDEC) Operator Control

The DDEC system is centered around a computer that is programmed to automatically control engine timing and fuel injection, providing maximum engine performance and fuel economy.

Some DDEC II® systems have an automatic engine shutdown option. This option will shut down the engine if potentially damaging conditions are detected. An override switch (on DDEC II engines, this switch is labelled "Override") is provided for emergency situations. It is mounted to the left of the ignition switch, and provides the driver with an extra 30 seconds of engine operating time.

Standard DDEC III® systems will shut down the engine if sensors indicate an emergency engine condition such as low coolant level, high coolant temperature, high oil temperature, or low oil pressure. If such a condition occurs, the yellow CHECK ENGINE light in the warning and indicator light module will come on. If the problem gets bad enough to cause possible engine damage, the DDEC III will gradually cut engine power down to 70 percent of original power. At that point, the red engine protection (ENG PROTECT) light will come on, and 30 seconds later, DDEC III will shut down the engine (if programmed).

If DDEC III detects low oil pressure, both the check engine and engine protection lights will come on and the engine will shut down in 30 seconds (if programmed).

NOTE: If the vehicle is in a hazardous place when the "Shutdown Engine" light illuminates, the driver must immediately press the "Override/Chk" switch or the engine will shut down in 30 seconds. Pressing the switch will give the driver an additional 30 seconds to move the vehicle. If this is still not enough time, the driver must press the switch again for another 30-second delay before engine shutdown.

Once the engine has shut down, cycle the ignition key off and then on, and press the "Override/Chk" switch to restart the engine.

The cruise control and PTO governor options are controlled in two ways:

Parking Brake Control Valve and Trailer Air Supply Valve

On Vehicles With Trailer Air Brake Hookup

The yellow diamond-shaped knob operates the parking brake valve. See Fig. 3.16 . Pull the knob out to apply both the tractor and the trailer spring parking brakes. Push the knob in to release the tractor spring parking brakes. Before the spring parking brakes can be released, the air pressure in either air brake system must be at least 65 psi (447 kPa).

1. Parking Brake Control Valve Knob
2. Trailer Air Supply Valve Knob
3. Dump Valve Toggle Switch

Fig. 3.16, Brake Valves/Air Suspension Dump Valve (typical switch locations)

The red octagonal knob operates the trailer air supply valve. See Fig. 3.16 . After the vehicle and its air hoses are connected to a trailer and the pressure in the air system is at least 65 psi (447 kPa), push the trailer air supply valve knob in (it should stay in) to charge the trailer air supply system and release the trailer spring parking brakes. Before disconnecting a trailer or when operating a vehicle without a trailer, pull the trailer air supply valve knob out.

Air Suspension Dump Valve, Optional

The air suspension dump valve allows the air in the vehicle air suspension to be quickly exhausted, lowering the rear of the vehicle. This makes it easier to connect to or disconnect from a trailer. A dump valve toggle switch on the dashboard exhausts and fills the air suspension. To prevent accidental activation, a safety release button on the switch must be pushed before the switch can toggle. See Fig. 3.16 .

Never exhaust air from the suspension while driving. If the air is exhausted, the suspension will not absorb road shocks and could be damaged.

AirLiner Plus Suspension, Optional

The AirLiner Plus suspension is used on vehicles with pusher or tag axles to improve traction performance. The system maintains an accurate leveling of frame height whether the vehicle is in motion or parked. The Meritor™ WABCO® ECAS (Electronically Controlled Air Suspension) system uses a height sensor mounted between the frame and the drive axle housing as well as other sensors to provide frame height information to a control unit mounted inside of the cab. The electronic control unit quickly lowers or raises the frame height, as necessary. Altering the height of the frame while the vehicle is parked can be performed using a hand-held remote control unit.

Stand away from the rear of the vehicle when raising or lowering the height of the frame. The ECAS system operates quickly, and contact could result in personal injury.

For the optional automatic function to work, the vehicle must be equipped with rear axle air suspension and ABS. Automatic Traction Control is recommended for optimal vehicle traction control.

Parking Brake Control Valve

Vehicles Without Trailer Air Brake Hookup

A diamond-shaped knob in the control panel operates the parking brake control valve. When the knob is out, the truck's spring parking brakes are applied. When the knob is in, the parking brakes are released. Before the parking brakes can be released, air pressure in either brake system must be at least 65 psi (447 kPa).

See Chapter 7 , under the heading "Air Brake System," for instructions on the use of the trailer air supply valve and parking brake valve.

Parking Brake Control Lever

On Vehicles With Hydraulic Brakes

If the vehicle is equipped with hydraulic brakes, a parking brake control lever is located on the cab floor near the gear shift lever. To apply the parking brake, depress the brake pedal, then pull up on the parking brake lever. To release the parking brake, depress the brake pedal and push the parking brake lever all the way down. Turning the knob counterclockwise decreases the effort needed to move the lever.

If the parking brake does not hold the vehicle securely, depress the brake pedal and release the parking brake. Turn the knob on the end of the lever clockwise to increase the parking brake application.

NOTE: Turning the knob clockwise will also increase the effort needed to apply or release the parking brake lever.

If the parking brake still doesn't securely hold the vehicle (after adjustment), check the brake lining thickness. For instructions, see Group 42 of the Business Class Trucks Maintenance Manual .

Cigarette Lighter, Optional

Push the lighter in to heat the element. The lighter will stay in until the element is hot, then it will pop out automatically.

Turn Signal Lever

The turn signal lever is mounted on the steering column. See Fig. 3.17 . Pushing the lever counterclockwise turns on the left-turn signal lights; pushing it clockwise turns on the right-turn signal lights. When one of the signal lights is on, a green indicator light flashes at the far left or far right of the warning and indicator light panel. When the turn is completed, the signal will cancel and the lever will return to the neutral position.

1. Turn Signal Lever
2. Hazard Warning Light Tab

Fig. 3.17, Turn Signal and Hazard Warning Light Switches

Hazard Warning Light Tab

The hazard warning light tab is located below the turn signal lever. See Fig. 3.17 . Hazard warning lights are operated by pulling the tab out. When the hazard warning light tab is pulled out, all of the turn signal lights and both of the indicator lights on the control panel will flash. To cancel the warning lights, move the turn signal lever upward or downward, then return the lever to the neutral position.

Headlight Dimmer Switch

Pull the turn signal lever upward to change from low-beam to high-beam headlights, or from high beam back to low beam. When the headlights are on high beam, a green light illuminates between the speedometer and tachometer. See Fig. 3.17 .

For vehicles built to operate in the United States, switching from low beams to high beams will switch off the road lights.

NOTE: The ignition switch must be on for the high beams to work.

Allison Automatic Transmission Controls

Allison automatic transmission models MD-CR and MD-WR are controlled by an electronic control unit (ECU). The ECU processes information from sensors, pressure switches, and the shift selector to automatically control the transmission according to programmed specifications. See Fig. 3.18 .

1. Indicator Panel
2. Mode ID

Fig. 3.18, Shift Selector

Vehicles with these transmissions have a red do-not-shift light in the lens and bezel assembly. Also, there is a service light in the indicator panel on the shift selector. With the ignition switch on, both lights come on for a few seconds, then if there is no problem with the transmission system, the lights will go out. Whenever there is a problem with the transmission system, the lights will come on and stay on as long as the problem exists.

If "service" is displayed in the indicator panel, some features may not work, but the vehicle can still be driven. If the do-not-shift light illuminates while driving (accompanied by eight short beeps from the shift selector), operating limits will be placed on the transmission, such as restricting upshifts and downshifts. However, the vehicle can still be driven to reach service assistance. In either situation, have the problem repaired as soon as possible. See the Allison Transmission Service Manual for troubleshooting procedures.

See Chapter 5 for complete transmission operating instructions.

Suspension Seat Adjustment Controls

All adjustment controls for a suspension seat are located on the seat base. See Chapter 2 for complete instructions.

Dome Light Switches

A two-bulb dome light, with a built-in three-position switch, is mounted in the center of the rear wall just beneath the cab roof.

When the switch is in the center position, the dome light will remain off whether or not the cab doors are open.

When the driver's side of the switch is pushed in, the light will remain on whether or not the cab doors are closed.

When the passenger's side of the switch is pushed in, the light will work with the driver's door contact switch. The light will be on when the driver's door is open, and off when the door is closed. As an option, the light will work in conjunction with the driver's and passenger's door contact switches to turn the light on when either of the cab doors is open, and turn it off when they are both closed.

Electric Horn

To sound the electric horn, push the button in the center of the steering wheel.

Air Horn, Optional

To sound the air-operated horn, pull the cable located above the driver's door.

Vernier Throttle Control, Optional

The vernier throttle control, located to the left of the steering column, can be used to adjust engine speed when the vehicle is parked. A "quick adjust" setting of engine speed is made by depressing the button on the control knob, then pushing in or pulling out the knob. Engine speed adjustments can then be made in smaller increments by turning the control knob in either direction.

Tilt Steering Wheel

The tilt steering wheel has a tilt range of 15 degrees, and a telescoping range of 2-5/8 inches (67 mm). A control lever is located just below the turn signal switch on the steering column. See Fig. 3.19 .

1. Control Lever
2. Tilt Wheel Assembly

Fig. 3.19, Tilt Wheel Assembly

After adjusting the seat to the desired ride position, unlock the steering column by pushing the control lever and holding it all the way down. Tilt the steering column to the desired position, then release the control lever to lock the steering column in place.

To adjust the height of the steering wheel, pull upward on the control lever. While holding the control lever in this position, move the steering wheel upward or downward to the desired position. Release the control lever to lock the steering wheel in place.

Make sure that the control lever is in the locked (neutral) position before driving the vehicle. Never try to adjust the height of the steering wheel or tilt the steering column while driving the vehicle. Doing so could cause loss of vehicle control, personal injury, and property damage.

Instrumentation Control Unit, Level I

The instrumentation control unit, level I (level I ICU) is the standard electronic dashboard. It can accept information from the various sensors installed on the vehicle and feed it to electronic gauges. Only air gauges operate mechanically.

There can be up to eight gauges on the driver's instrument panel, six electronic and two mechanical.

The dash message center is the heart of the level I ICU. It has two parts, a set of 26 warning and indicator lights similar to those found on a conventional warning and indicator light module and a dash driver display screen. The dash driver display screen is a one-line by seven-character liquid crystal display (LCD) that normally shows odometer readings. Below this display is a smaller one-line by three-character LCD that shows voltmeter readings.

Warning and Indicator Lights

There can be up to 26 warning and indicator lights installed in the level I ICU. See Fig. 3.20 .

Typical installation shown. Location of legends installed in the top row may vary, and other legends may be specified.

1. Stop Engine Warning (Cummins engine only)
2. Eng. Fan On Indicator, Optional
3. Do Not Shift Indicator, Optional
4. ECAS Failure Warning, Optional
5. ECAS Transfer Indicator, Optional
6. Low Washer Fluid Indicator, Optional
7. Wheel Spin Indicator, Optional
8. EBS Warning, Optional
9. Water In Fuel Indicator, Optional
10. Check Engine Indicator
11. Engine Protection Warning, Optional
12. No Charge Indicator, Optional
13. Tractor ABS Warning
14. Transmission Temperature Warning, Optional
15. Trailer ABS Warning
16. Low Oil Pressure Warning
17. High Coolant Temperature Warning
18. Fasten Seat Belt Warning
19. Parking Brake On Warning
20. Recirculated Air Indicator, Optional
21. Air Restriction Indicator, Optional
22. Left-Turn Signal
23. Low Battery Voltage Warning
24. Dash Driver Display Screen
25. High Beam Indicator
26. Low Air Pressure Warning
27. Right-Turn Signal

Fig. 3.20, Level I ICU Dash Message Center

There are four rows of lights in the dash message center. Lights installed in the top row are optional, and their positions may vary. The lights in the bottom three rows are installed in fixed positions on all vehicles. Most are standard, but a few are optional.

The green right- and left-turn signal lights flash on and off whenever the outside turn signals are flashing.

The blue high-beam indicator light illuminates when the headlights are on high beam.

The amber CHECK ENGINE indicator light illuminates if an engine condition exists such as low coolant level, high coolant temperature, or low oil pressure. It also illuminates when a fault is detected or recorded.

The red ENGINE PROTECT warning light illuminates to indicate that the protection system available on the engine has been activated.

The red low oil pressure (oil can symbol) warning light and buzzer activate whenever the engine oil pressure goes below a minimum level specified by the engine manufacturer (see the engine manual).

The red high coolant temperature (thermometer symbol) warning light and buzzer activate whenever the coolant temperature goes above a maximum level specified by the engine manufacturer (see the engine manual).

The red fasten seat belt warning light illuminates whenever the ignition switch is turned on, and stays on for 15 seconds.

The red parking brake on (!P symbol) warning light illuminates whenever the parking brake is engaged. The buzzer sounds if the vehicle is moving at a speed greater than 2 mph (3 km/h) with the parking brake set.

The amber RECIRC AIR indicator light illuminates whenever the ventilating system is switched to recirculated air.

The red low air pressure (circle with arrows symbol) warning light and buzzer activate whenever air pressure in the primary or secondary air reservoir falls below 64 to 76 psi (440 to 525 kPa).

The Trailer ABS lamp will illuminate at vehicle start-up and when there is a fault in the trailer ABS system. The lamp will only operate when a compatible trailer is connected to the tractor before ignition. For more information, see Chapter 7 .

Depending on options installed, other warning and indicator lights can be present. The optional indicator lights that are available include: alternator no charge indicator, transmission temperature warning, check transmission indicator, range inhibit indicator, air restriction indicator, engine fan on indicator, ECAS (electronic suspension) transfer indicator, ECAS failure warning, low washer fluid indicator, low battery voltage warning, EBS (electronic braking system) warning, wheel spin indicator, and water in fuel indicator.

NOTE: The functions of the ABS warning lights are explained under "Meritor™ WABCO® Antilock Braking System (ABS), Air Brake Systems" later in this chapter.

Level I ICU Ignition Sequence

If the headlights are turned on, the screen displays the odometer and waits for the ignition to be turned on.

When the ignition is turned on, all of the electronic gauges complete a full sweep of their dials, the warning and indicator lights light up, and the buzzer sounds for three seconds. See Fig. 3.21 .

NOTE: The air gauges do not sweep.

The following lights go on during the ignition sequence:

Fasten Seat Belt Warning

Low Battery Voltage Warning

High Coolant Temperature Warning

Low Engine Oil Pressure Warning

Low Air Pressure Warning

Parking Brake On Indicator

All engine warning lights, including Engine Protection, Check Engine, and Stop Engine (Cummins only)

All ABS warning lights, including Wheel Spin, Tractor ABS, and Trailer ABS (if installed)

NOTE: While the engine and ABS warning lights go on during the ignition sequence, they are not controlled by the level I ICU, but by their own system ECU (electronic control unit).

Once the ignition switch has been turned on, the level I ICU performs a self-test, looking for active faults. During the first half of the self-test, all segments of the display illuminate as follows: 888888.8 . The voltmeter display also illuminates, but with the value 18.8 . During the second half of the self-test, the software revision level is displayed.

If there are no active faults, the screen displays the odometer.

If the level I ICU has received active fault codes from other devices, it displays them one after the other until the parking brake is released or the ignition switch is turned off. Once the parking brake is released, the level I ICU displays the odometer again.

Fig. 3.21, Level I ICU Ignition Sequence

Mode/Reset Switch

The mode/reset switch ( Fig. 3.22 ) is located on the right side of the instrument cluster. The mode/reset switch is used to scroll through the displays on the message display screen, and to reset the trip distance and trip hours values to zero.

Fig. 3.22, Mode/Reset Switch

See Fig. 3.23 for the state diagram for the LCD display cycle.

NOTE: The systems diagnostics test is used by trained personnel to retrieve fault codes and other diagnostic information pertaining to the vehicle.

Fig. 3.23, ICU3 Mode Reset LCD Display Cycle

When the odometer reading is displayed and the parking brake is applied:

Press the mode/reset switch once and the trip distance will display.

Press the mode/reset switch a second time and the trip hours (engine hours) will display.

Press the mode/reset switch a third time and the SELECT screen and the current units, MI or KM, will display.

Press the mode/reset switch a fourth time to return to the odometer reading.

To reset trip miles and/or trip hours to zero, press the mode/reset switch for 1 second or longer. To toggle between MI (miles) of KM (kilometers), press the mode/reset switch while in the SELECT screen.

Warning and Indicator Lights, Right-Hand-Drive and Mechanical Engine Vehicles

For right-hand-drive and mechanical engine vehicles, a warning and indicator light module, located below the speedometer and tachometer, houses all of the standard and optional warning and indicator lights. See Fig. 3.24 .

1. Low Oil Pressure/High Coolant Temperature Warning
2. Low Coolant Level Warning
3. Low Engine Oil Level Warning
4. Alternator Warning
5. Brake System Warning
6. Tractor ABS Warning
7. Wheel Spin Indicator
8. Deep Snow/Mud Indicator
9. Stop Engine/Engine Protection Warning
10. Check Engine Indicator
11. Cold Start Indicator
12. Intake-Air Restriction Indicator
13. Do Not Shift Indicator
14. Transmission Temperature Warning (automatic transmission)
15. Water in Fuel/Water Separator Warning
16. Parking Brake Warning

Fig. 3.24, Warning and Indicator Lights (right-hand-drive and mechanical engine vehicles)

For all other vehicles, the warning and indicator lights are located above the speedometer and tachometer, in the level I ICU dash message center. See Fig. 3.20 . The ICU is the control module for these lights.

On right-hand-drive and mechanical engine vehicles, all of the standard and optional warning and indicator lights are housed in a lens and bezel assembly located between the speedometer and tachometer.

Standard Indicator Lights

Standard indicator lights include:

The green right- and left-turn signal lights, which flash on and off whenever the outside turn signal lights are flashing.

The blue high-beam indicator light, located above the speedometer and tachometer, illuminates when the headlights are on high beam.

Standard Warning System

Standard Warning Lights

Standard red warning lights are for alternator no-charge (battery symbol), the parking brake ("P" symbol), and the brake system (! symbol). See Fig. 3.24 .

The red parking brake warning light illuminates whenever the parking brakes are activated and the ignition is on.

Whenever conditions cause the brake system warning light to come on, a warning buzzer also alerts the driver.

If equipped with air brakes, the brake system warning light and buzzer activate whenever air pressure in the primary or secondary air reservoir falls below 64 to 76 psi (441 to 524 kPa).

If equipped with hydraulic brakes, the warning light goes on and the buzzer sounds when the fluid level is low or when there is a fluid pressure problem within the master cylinder. Also, the buzzer will sound when the driver's door is opened if the parking brake control lever has not been applied.

Optional Warning and Indicator Lights

The high coolant temperature/low oil pressure (oil can/thermometer symbol) warning light and buzzer activate whenever the engine coolant temperature exceeds a preset point determined by the engine manufacturer. See Table 3.1 for this temperature.

Maximum Coolant Temperature
Engine Model	°F (°C)
Mercedes-Benz MBE900	222 (105)
Caterpillar (all models)	210 (99)
Cummins M11 and C Series	212 (100)
Cummins B Series	210 (99)
Detroit Diesel	210 (99)

Table 3.1, Maximum Coolant Temperature

The high coolant temperature/low oil pressure warning light and buzzer also activate whenever the oil pressure falls below the minimum oil pressure recommended by the engine manufacturer. See Table 3.2 .

Oil Pressure^*
Engine Model	Oil Pressure at Idle Speed psi (kPa)	Oil Pressure at Rated Speed psi (kPa)
Mercedes-Benz MBE900	7 (50) min.	36 (250) min.
Caterpillar C-10	10 to 20 (69 to 138)	30 to 45 (207 to 310)
Caterpillar C-12	10 (69) min.	45 (310) min.
Cummins M11	10 (69) min.	35 to 45 (241 to 310)
Cummins B and C Series	10 (69) min.	30 (207) min.
Detroit Diesel	12 (83) min.	50 (345) min.

^* Oil pressures are given with the engine at operating temperature. With the engine cold, oil pressures may be higher.

Table 3.2, Oil Pressure

Other optional warning or indicator lights may include: intake air preheater, oil level, automatic transmission fluid temperature, low coolant level, do-not-shift, check transmission, range inhibit, intake-air restriction, check engine, engine protection.

When the ignition is turned on, oil- and brake-system warnings (as equipped) activate until the engine starts and minimum pressures are exceeded. If the low-oil warning light or brake system warning light remains lit after running the engine for 15 seconds, shut down the engine an determine the cause. See the vehicle service manual for repair procedures.

IMPORTANT: If the warning system does not activate when the ignition is turned on, repair the system to provide warning protection for oil pressure, coolant temperature, and the brake system.

Kysor Vehicle Protection System, Optional

The Kysor system is an electronically-controlled warning and engine shutdown system. See Fig. 3.24 .

Engine Functions

The system monitors engine coolant temperature, coolant level, and oil pressure.

If the engine overheats, a warning light illuminates and a buzzer sounds. The temperature that triggers the warning light and buzzer varies with engine type and is programmed into the system at the factory. If the temperature continues to rise to critical levels, the engine protection light illuminates and the engine will shut down.

If the coolant level drops below a sensor in the cooling system, the low coolant level light illuminates and a buzzer sounds. After 30 seconds, the system will shut down the engine.

If the engine oil pressure drops below a preset level, the low oil pressure light illuminates and a warning buzzer sounds. If the oil pressure drops to a preset critical level, the engine protection light illuminates and the engine will shut down.

All shutdown features have an automatic override. If the vehicle needs to be moved to a safe location after a shutdown, just start the engine. It will run for about 30 seconds before shutting down again.

Meritor™ WABCO® Antilock Braking System (ABS), Air Brake Systems

The Meritor WABCO Antilock Braking System (ABS) may have the following warning lights: a tractor warning (TRAC ABS) light, a wheel spin (WHL SPIN) indicator light, and a DEEP SNOW/MUD indicator light. See Fig. 3.24 .

If equipped with the tractor ABS system, the tractor warning (TRAC ABS) light illuminates after the engine is started. See Fig. 3.24 . Once the vehicle moves faster than about four mph (six km/h), the warning light goes out only if all of the tractor's ABS components are working.

The wheel spin (WHL SPIN) indicator light illuminates if one of the drive wheels spins during acceleration. See Fig. 3.24 . The light goes out when the wheel stops spinning. A label on the dash explains what actions should be taken when the wheel spin indicator light illuminates. See Fig. 3.25 .

Fig. 3.25, Dash Label

If equipped with an electronic engine, an automatic traction control (ATC) system may be installed. On these vehicles, the ATC system automatically reduces wheel spin during reduced-traction starts.

An "ATC Function" switch (if equipped), may be used under more adverse conditions. Turning on this switch illuminates the DEEP SNOW/MUD indicator light. The ATC system now allows some wheel spin (for example, to help burn through a thin layer of ice) during reduced-traction starts. See Fig. 3.24 .

IMPORTANT: If any of the ABS warning lights do not work as described above, or come on while driving, repair the ABS system immediately to ensure full antilock braking capability.

An ABS CHK switch is located below the dash panel on the right side of the steering column, and is used to read system fault codes on the WHL SPIN light. See Section 42.36 of the Business Class® Trucks Service Manual for troubleshooting procedures.

IMPORTANT: If the vehicle is equipped with the ATC system, turning on the ABS CHK switch will reduce engine speed to idle. This will occur whether the vehicle is stopped or is being driven. Also, the WHL SPIN light will come on. If these conditions occur, turning the ABS CHK switch off will return the engine to full function capability.

See the brake system operating instructions in Chapter 7 for more information.

Meritor™ WABCO® Antilock Braking System (ABS), Hydraulic Brake Systems

If equipped with the ABS system, the dash warning light (TRAC ABS) illuminates after the engine is started. See Fig. 3.24 . Once the vehicle moves faster than about four mph (six km/h), the warning light goes out only if all of the tractor's ABS components are working.

IMPORTANT: If the TRAC ABS warning light does not work as described above or illuminates while driving, repair the ABS system immediately to ensure full antilock braking capability.

An ABS CHK switch is located below the dash panel on the right side of the steering column and is used to read system fault codes on the TRAC ABS light. See Section 42.36 of the Business Class® Trucks Service Manual for troubleshooting procedures.

See the brake system operating instructions in Chapter 7 for more information.

Bendix Antilock Braking System (ABS)

With the Bendix Antilock Braking System (ABS), the tractor warning light (TRAC ABS) illuminates after the key is turned on. The warning light goes out only if all of the tractor's ABS components are working properly. See Fig. 3.24 .

Vehicles equipped with a Bendix ABS system may also be equipped with an automatic traction control (ATC) system. The ATC system automatically controls wheel spin during reduced-traction starts.

The wheel spin indicator light (WHL SPIN) illuminates if one of the drive wheels spins during acceleration). The light goes out when the wheel stops spinning. The Bendix system will either reduce engine torque or apply gentle brake pressure to force the differential to drive the stationary or slowly spinning wheel. If slippery road conditions continue, engage the axle lock. See Fig. 3.24 .

IMPORTANT: If any of the ABS warning lights do not work as described above, or come on while driving, repair the ABS system immediately to ensure full antilock braking capability. See Group 42 in the Business Class® Trucks Service Manual for troubleshooting procedures.

See the brake system operating instructions in Chapter 7 for more information.

Collision Warning System (CWS), Eaton VORAD EVT–300, Optional

The Eaton VORAD EVT–300 is a computerized collision warning system (CWS) that uses front-mounted and side-mounted (optional) radar to continuously monitor vehicles ahead of and alongside your vehicle.

The system warns of potentially dangerous situations by means of visual and audible alerts. The system performs in fog, rain, snow, dust, smoke, and darkness. To be detected, objects must be within the radar beam's field of view and provide a surface area that can reflect back the radar beam.

The front-looking antenna assembly transmits radar signals to, and receives them back from, vehicles and objects ahead. This allows the determination of the distance to, relative speed of, and angle to the target of vehicles and objects ahead. The system uses this information to warn the driver of potentially dangerous situations.

Optional side sensor(s) mounted on the side of the vehicle also transmit and receive radar signals for a distance of 2 to 10 feet (0.5 to 3 meters) alongside your vehicle. The side sensor(s) provide a 15 degree vertical by 15 degree horizontal beam pattern. The side sensor(s) can detect unseen vehicles and objects moving and stationary adjacent to your vehicle.

The Eaton VORAD EVT–300 Collision Warning System (CWS) is intended solely as an aid for an alert and conscientious professional driver. It is not intended to be used or relied on to operate a vehicle. Use the system in conjunction with rearview mirrors and other instrumentation to safely operate the vehicle. Operate this vehicle, equipped with the EVT–300 Collision Warning System, in the same safe manner as if the EVT–300 Collision Warning System were not present.

The EVT–300 Collision Warning System is not a substitute for safe, normal driving procedures, nor will it compensate for any driver impairment, such as drugs, alcohol, or fatigue.

The EVT–300 Collision Warning System may provide little or no warning of hazards such as pedestrians, animals, oncoming vehicles, or cross traffic.

On vehicles with SmartCruise, the vehicle will not deactivate cruise control for stationary targets, such as a car stopped in your traveling lane.

Failure to drive safely and use the system properly could result in personal injury and/or death and severe property damage.

Driver Display Unit (DDU)

NOTE: All system controls are located on the DDU. See Fig. 3.26 . Indicators to inform the driver about the system's operation are located on both the DDU and the optional side sensor display.

1. Red System Failure Indicator Light
2. Green Power ON/Driver's Card Status Indicator Light
3. Volume Control and Power ON/OFF Knob
4. Speaker
5. Range Knob
6. Green SC Indicator Light
7. Photo Light Sensor
8. Driver's Identification Card Slot
9. Red Alert Light
10. Orange Alert Light
11. Yellow Alert Light
12. Distance/Danger Alert Lights

Fig. 3.26, Driver Display Unit, EVT-300

The DDU controls system power, range for vehicle warnings, speaker volume, and all other system functions. At the lower front edge of the DDU, a slot is provided to insert the optional driver's identification card. Alert and indicator lights advise of multiple warning levels, system power, system failure, and, if so configured, failure of the driver to insert the identification card.

A light sensor automatically adjusts alert and indicator light brightness depending on cab lighting conditions. A small speaker provides audible alert tones to warn of closing on an object ahead and, when equipped with an optional side sensor, of objects alongside when the turn signal is activated in preparation for a lane change. Additional tones indicate speaker volume, system failure, driver's card status, and data extraction pass or fail.

The green power-on/driver's card (optional) status indicator light illuminates when the system is activated and the power-on LED test is complete. If the system is configured to require that the driver's card be read, and it is not, the ON light blinks continuously.

Push in the volume control and power ON/OFF knob to turn power on or off. Turn the knob left or right to increase or decrease speaker volume. Press and hold the knob for 5 seconds and then release it to activate the failure display mode.

NOTE: The system may be configured to have no on/off capability and the volume may be configured to allow only some volume control.

The speaker is located under the top cover of the DDU. It sounds audible tones to alert the driver to potential hazards. Volume may be restricted to a range above a minimum level.

NOTE: This is a configurable electronic parameter.

Rotate the range knob (if enabled) to change the first alert detection range from 3 to 2 seconds. This will also change the second alert detection range from 2 to 1.75 seconds. Push and hold the knob for 5 seconds to activate the accident reconstruction function and freeze the most recent data in half of the allocated memory.

NOTE: The system may be configured to prevent adjustment of the range levels.

The red system failure indicator light illuminates if a system problem is detected. Press and hold the volume control knob for 5 seconds to display fault codes. The fault codes will be blinked out as a pattern of flashes on this indicator light. See Table 3.3 for fault codes.

Fault Codes (blink codes)
Fault Code	Suspect Failure
11	Central Processing Unit (CPU)
12	CyberCard
13	Driver Display Unit (DDU)
14	Antenna Assembly
15	Right Side Sensor
16	Left Side Sensor
21	Right-Turn Signal
22	Left-Turn Signal
23	Brake
24	Speed
25	SmartCruise
31	J1587
32	J1939
33	VBUS
34	DDU Communications
35	Antenna Assembly Communications
41	No Fault or End of Fault Codes

Table 3.3, Fault Codes or Blink Codes

The green SC indicator light will flash 8 times if the range knob is pressed to store accident reconstruction information. It will also flash 8 times after the system is activated, after the power-on LED test is finished, and if accident reconstruction data was previously stored.

The photo light sensor senses lighting conditions in the cab and automatically adjusts the intensity of the indicator and alert lights.

If the system's configuration requires, insert the driver's identification card in the slot at the lower front edge of the DDU. A high-pitched tone will sound when the driver's identification card has been successfully read. One low tone will sound if the driver's card has been unsuccessfully read. If so configured, a repeated low tone will sound if the system is on and the requested driver's card has not been inserted.

The yellow alert light illuminates when an object is detected within the system's maximum range of 350 feet (107 meters) on a straight road. Range is reduced in curves by the turn radius of the curve. This light also illuminates when the proximity alarm threshold is crossed.

10.

The yellow and orange alert lights illuminate when your vehicle is within a 3-second following interval behind another vehicle in the same lane. If you are within a 2-second following interval, and closing on the vehicle ahead, a warning tone will also sound.

11.

The yellow, orange, and red alert lights illuminate when you are 1 second (and less than 1 second) behind a vehicle. If the vehicle ahead is opening the interval, no tone will sound. If you are closing the interval, double tones will sound. Within a 1/2-second or less following interval, opening or closing, the tones will repeat twice per second.

12.

If a stationary vehicle or object, or an object moving less than 3.4 mph (5.5 km/h) in the same lane is detected within 220 feet (67 meters) and within 3 seconds, all three alert lights will illuminate and the double tones will sound. This warning overrides all others and is not affected by the range control knob setting.

IMPORTANT: The system is disabled in turns with a radius of less than 750 feet (230 meters) and when the brakes are applied.

13.

If your vehicle is traveling less than 2 mph (3 km/h) and an object is detected less than 15 feet (4.5 meters) in front of your vehicle, and the closing rate is more than 1/2 mph (1 km/h), the yellow alert light will illuminate and a low-frequency double tone will sound. This is the proximity alert.

NOTE: All warnings apply only to objects within the maximum detection range and in your lane. Proximity alert tones and vehicle-closing 1/2-second and 2-second following interval tones are configured items. All tones are disabled in sharp turns or when the brakes are applied. If the configuration permits, the 3-second and 2-second alert levels may be adjusted with the range control knob. A single low-frequency tone sounds when a system failure is detected. A medium-frequency tone sounds when the volume control level is changed. Successful downloading of Eaton Vehicle Information Management System (EVIMS) data will cause a double tone to sound. Unsuccessful downloading will cause a low-frequency tone to sound.

14.

A failure of the optional side sensor(s) will cause a continuous red light on the side sensor display to appear.

Side Sensor Display, Optional

The yellow indicator light illuminates continuously when no vehicle is detected by the side sensor(s). See Fig. 3.27 .

1. Red Alert Light (vehicle or object detected)
2. Photo Light Sensor
3. Yellow Indicator Light (no vehicle or object detected)

Fig. 3.27, Side Sensor Display, Optional

The photo light sensor senses lighting conditions in the cab and automatically adjusts the intensity of indicator and alert lights.

The red alert light illuminates when objects are detected by the side sensor(s). If the right turn signal is activated and the side sensor detects an object, the red alert light will illuminate and the DDU speaker will sound a high-frequency double tone. This tone is sounded only once per activation of the turn signal. The red light will also illuminate and stay on if a failure of the side sensor is detected.

Special Road Situations

Certain special road situations may affect the system's ability to detect objects. These situations include the effects of curves, dips, and hills which can provide an unexpected result:

NOTE: A warning may sound when an object is detected in front of the vehicle even though the driver intends to turn away or stop before reaching the object.

When an object is detected in a very sharp right- or left-hand turn, the audible alarm will not sound.

When approaching a curve, before turning into it, alarms may sound and lights illuminate because of an object off of the road, directly in line with your vehicle. This will not occur when the brakes are applied.

Elevated obstacles, such as overpasses and overhead signs, may be detected when approaching a roadway descending to a lower elevation.

Vehicles cannot be detected on the other side of a hill. An alarm will not sound until the object is within the antenna assembly's field of view.

On approaching a steep hill, objects above the beam cannot be detected. Generally, the beam hitting the road surface does not cause an alarm.

The side sensor only detects objects within its field of view, next to your vehicle. A vehicle farther back, behind the field of view, will not be detected.

The side sensor range is set to detect average sized vehicles, 2 to 10 feet (0.5 to 3 meters) away, in the adjacent lane. The side sensor provides a 15 degree vertical by 15 degree horizontal beam pattern.

The radar beam of the CWS will detect near range cut-ins of approximately 30 feet (9 meters) or less, depending on the angle of entrance into the lane in front of your vehicle.

Heavy rain or water spray at the side sensor may temporarily prevent the system from providing adequate warnings.

Failure to drive safely and use the system properly could result in personal injury and/or death and severe property damage.

NOTE: A continuous fixed object on the right side of the vehicle such as a guard rail, wall, tunnel, or bridge may cause the side sensor alert light to stay on.

In Case of Accident

The optional vehicle accident reconstruction capability provides two segments of system data, one of which can be stored in system memory. Push and hold the DDU range knob for at least 5 seconds to store the first segment. Within 6 seconds, the green SC indicator light will blink rapidly 8 times, confirming that the data has been saved. If the range knob is pushed again, a fail tone will sound. After the first segment is saved, the second segment runs continuously, but only contains the last 10 minutes (approximately) of system data. The system will cease recording data 30 seconds after the vehicle comes to a stop.

NOTE: Once the first memory segment is frozen, the other can't be frozen. Only by disconnecting the main CPU connector can the second memory segment be preserved. If you desire immediate downloading and interpretation of accident reconstruction data, you must return the CPU to Eaton VORAD. However, after 30 days the frozen information will automatically clear if the vehicle is driven.

Maintenance and Diagnostics

Keep the antenna assembly and side sensor(s) free of a buildup of mud, dirt, ice, or other debris that might reduce the system's range.

The system tests itself continuously and evaluates the results every 15 seconds. If a problem is detected with the front radar system, the red FAIL light on the DDU illuminates continuously as long as the failure is active. The corresponding fault code is stored in the CPU's memory.

Both active and inactive fault codes can be indicated by the DDU when the system is placed in failure display mode. Inactive faults are those that have occurred and have cleared. Active faults are still present. Fault codes provide the driver the ability to record the system faults during a trip and to notify his maintenance department or Eaton VORAD. See "Failure Display Mode/Fault Codes" below. In this mode, specific fault codes are indicated by the pattern of blinks of the driver display unit red FAIL light.

Each fault code is a two-digit number, as shown in Table 3.3 . The red FAIL light blinks the same number of times as the first digit, a pause of approximately 3/4 of a second follows, then the light blinks the same number of times as the second digit.

Additional fault codes are blinked out at intervals of approximately 3 seconds. After all the fault codes have been blinked out, a code 41 will be blinked out.

Failure Display Mode/Fault Codes

NOTE: If the vehicle does not have ON/OFF control on the DDU, press and hold the volume knob after the ignition key is turned on and the 15-second self-test is complete.

Press and hold the DDU volume control and power ON/OFF knob for at least 9 seconds. The system will turn off if you release the knob before 9 seconds. After 9 seconds, the DDU FAIL light begins to blink out the fault codes. After a 3-second interval additional fault codes, if present, will be blinked out. A code 41 will be blinked out either if no faults are found or when all fault codes have been blinked out.

Position the DDU range knob to the left to blink active fault codes and to the right to blink inactive codes.

To review, test, and clear all fault codes from system memory, use a hand-held diagnostic tool orServiceRanger.

Instruments

For the standard electronic engine gauge layout, see Fig. 3.28 .

For the standard gauge layout for right-hand-drive and mechanical engine vehicles, see Fig. 3.29 .

1. Transmission Temperature Gauge, Optional
2. Coolant Temperature Gauge
3. Engine Oil Pressure Gauge
4. Dash Message Center
5. Fuel Gauge
6. Primary Air Pressure Gauge
7. Mode/Reset Push Button, Optional
8. Secondary Air Pressure Gauge
9. Speedometer
10. Tachometer, Optional

Fig. 3.28, Typical Gauge Layout, Electronic Engine Vehicles

1. Voltmeter, Optional
2. Coolant Temperature Gauge
3. Engine Oil Pressure Gauge
4. Tachometer, Optional
5. Speedometer
6. Fuel Gauge
7. Primary Air Pressure Gauge
8. Secondary Air Pressure Gauge
9. Warning and Indicator Lights

Fig. 3.29, Typical Gauge Layout (right-hand-drive and mechanical engine vehicles)

Speedometer

A speedometer registers vehicle speed in both miles per hour (mph) and kilometers per hour (km/h). Standard speedometer gauges are equipped with an odometer that records total distance traveled in either miles or kilometers.

Tachometer, Optional

A tachometer indicates engine speed in revolutions per minute (rpm) and serves as a guide for shifting the transmission and keeping the engine in the appropriate rpm range. For low idle and rated rpm, see the engine identification plate.

The tachometer may include an engine hour meter. An engine hour meter records continuous operating hours of the engine. In cases where actual mileage does not indicate overall usage, maintenance and lubrication intervals for the engine and engine-operated equipment can be determined by operating hours.

Coolant Temperature Gauge

During normal engine operation, the coolant temperature gauge should read 175 to 203°F (79 to 95°C). If the temperature remains below 160°F (71°C) or exceeds the maximum temperature shown in Table 3.1 , inspect the cooling system to determine the cause. See Section 20.00 of the Business Class® Trucks Service Manual for troubleshooting and repair procedures.

Engine Oil Pressure Gauge

The oil pressure gauge should read as shown in Table 3.2 .

A sudden decrease or absence of engine oil pressure may indicate mechanical failure. Bring the vehicle to a safe stop, and investigate the cause to prevent further damage. Do not operate the engine until the cause has been determined and corrected.

Voltmeter, Optional

The voltmeter gauge is optional on the control panels without an ICU. On the ICU control panels, the voltmeter readings are displayed on the lower line on the dash message center.

The voltmeter indicates the vehicle charging system voltage when the engine is running and the battery voltage when the engine is stopped. By monitoring the voltmeter, the driver can be aware of potential charging system problems and have them fixed before the batteries discharge enough to create starting difficulties.

The voltmeter will normally show approximately 13.7 to 14.1 volts when the engine is running. The voltage of a fully charged battery is 12.7 to 12.8 volts when the engine is stopped. A completely discharged battery will produce only about 12.0 volts. The voltmeter will indicate lower voltage as the vehicle is being started or when electrical devices in the vehicle are being used.

If the voltmeter shows an undercharged or overcharged condition for an extended period, have the charging system and batteries checked at a repair facility.

On a vehicle equipped with a battery isolator system, the voltmeter measures the average voltage of all of the batteries when the engine is running. When the engine is stopped, the voltmeter shows only the gel cell battery voltage and does not indicate the voltage of the engine-starting batteries.

Gel cell batteries can be damaged if the battery voltage is allowed to drop below 12.0 volts or if the charging voltage is more than 14.1 volts. Start the engine to recharge the gel cell before the battery becomes fully discharged. If an external charger is needed, disconnect the gel cell battery and use only an external battery charger that has been approved for gel cell batteries.

Primary and Secondary Air Pressure Gauges

These air pressure gauges register the constant pressure in the primary and secondary air systems. Normal pressure, with the engine running, is 95 to 125 psi (655 to 862 kPa) in both systems. A low-air-pressure warning light and buzzer connected to both the primary and secondary systems, activate when air pressure in either system drops below a minimum pressure of 62 to 68 psi (427 to 469 kPa). When the engine is started, the warning light and buzzer remain on until air pressure in both systems exceeds minimum pressure. An air pressure gauge that registers pressure in both the primary and secondary systems may be installed on some vehicles.

Fuel Gauge

The fuel gauge indicates the amount of fuel in the fuel tank(s).

Intake-Air Restriction Indicator

An intake-air restriction indicator measures the vacuum on the engine side of the air cleaner at the air cleaner outlet. See Fig. 3.30 . If the yellow signal stays locked at or above the values shown in Table 3.4 after the engine is shut down, service the air cleaner, then reset the indicator by pressing the reset button.

Fig. 3.30, Intake-Air Restriction Indicator (installation typical)

Intake-Air Restriction
Engine Model^*	Service at or Above
Mercedes-Benz MBE900	22 inH₂O
Caterpillar	25 inH₂O
Cummins	25 inH₂O
Detroit Diesel	25 inH₂O

^* Turbocharged engines must be checked at full load and governed engine speed.

Table 3.4, Intake-Air Restriction

NOTE: Avoid opening the air cleaner and disturbing the seals or filter element until the yellow signal stays locked at or above the value shown in Table 3.4 . When this occurs, the air cleaner needs replacing; however, immediate engine shutdown is not necessary.

Transmission Oil Temperature Gauge, Optional

With an Allison automatic transmission, the transmission oil temperature gauge reading should not exceed 250°F (121°C) during normal operation. A warning light will activate to alert the driver.

A sudden increase in transmission oil temperature that is not caused by a load increase may indicate mechanical failure. Bring the vehicle to a safe stop, and investigate the cause to prevent further damage. Do not operate the vehicle until the cause has been determined and corrected.

Heater and Air Conditioner

A dash-mounted climate control panel allows you to control all of the heating, air conditioning, defrosting, and ventilating functions. See Fig. 3.31 or Fig. 3.32 .

1. Fan Switch
2. Air Selection Switch
3. Temperature Control Switch

Fig. 3.31, Climate Control Panel, Equipped With Heater Only

1. Fan Switch
2. Air Selection Switch
3. Temperature Control Switch
4. AC On-Off Lever at the Off Position
5. Air Source Lever at the Fresh Air Position

Fig. 3.32, Climate Control Panel, Equipped With Heater and Air Conditioner

A three-speed fan switch controls the flow of fresh or recirculated air to any selected air outlets at the windshield, door windows, dashboard face, and cab floor. If equipped with air conditioning, an on/off control lever is installed with the fan switch.

An air selection switch controls the direction of warm or cool air either to the feet, to feet and windshield, or to the windshield (defrost).

If equipped with air conditioning, the air selection switch controls the direction of warm or cool air either to the face, to face and feet, to feet and windshield, or to the windshield (defrost). An air-source lever is also used to control the mixing of recirculated cab air with fresh air from the outside.

A temperature control switch is used to select the desired temperature. Turn the switch counterclockwise for cool air, or clockwise for warm air.

All of the dash-face outlets have adjustable louvers that pivot right and left, and up and down. Close an outlet by moving the lever all the way up or, open an outlet by moving the lever all the way down. See Fig. 3.33 .

Fig. 3.33, Dash-Face Outlet

Windshield defrost outlets can be moved to direct air flow, but the door window defrost outlets have nonadjustable louvers.

See Fig. 3.34 for location and function of all dash outlets.

1. Driver's Door Window Defrost Outlet
2. Windshield Defrost Outlets
3. Passenger's Door Window Defrost Outlet
4. Floor Outlet
5. Dash and Door Window Vent
6. Center Dash Vents

Fig. 3.34, Air Outlet System

IMPORTANT: If equipped with air conditioning, do not operate the heater and air conditioning system with the air source lever in the recirculation mode for more than 20 minutes. This will prevent the buildup of fumes or odors inside of the cab (for example, from smoking).

Defogging and Defrosting

Turn the temperature control switch all the way clockwise for warm air, turn the fan switch to off and, if so equipped, move the air conditioning on/off lever to off before starting the engine.

Remove any ice or snow from the outside of the windshield, door windows, and fresh air inlet grille.

With the engine at operating temperature, turn the fan switch to the highest speed. Leave it in this position for 30 seconds. This will clear the system of moist air.

Move the air selection switch to the windshield (defrost) position, turn the air source lever to the fresh air position, and if so equipped, move the air conditioning on/off lever to the on position as shown in Fig. 3.35 . In this position, warm, dry air is directed to the windshield.

1. Fan Switch
2. Air Selection Switch
3. Temperature Control Switch
4. Air Source Lever at the Fresh Air Position
5. Air Conditioning On/Off Lever at the On Position

Fig. 3.35, Defogging and Defrosting Settings

IMPORTANT: If equipped with an air source lever, do not operate the heater and air conditioning system with the air source lever in the recirculation mode for more than 20 minutes. This will prevent the buildup of fumes or odors inside of the cab (for example, from smoking).

NOTE: At the defrost position, airflow is directed to the windshield outlets, the extreme left and right dash-face outlets, and the door window outlets.

Heating

With the engine at operating temperature, move the temperature control switch all the way clockwise for heat.

Turn the fan switch to the highest speed.

Move the air selection switch to the desired setting and move the air source lever to the fresh air position as shown in Fig. 3.36 .

1. Fan Switch
2. Air Selection Switch
3. Temperature Control Switch
4. Air Source Lever at the Fresh Air Position
5. Air Conditioning On/Off Lever at the Off Position

Fig. 3.36, Heating Settings

IMPORTANT: If the windows start to fog, move the air selection switch to defrost (windshield) and make sure that the fan is on. To defrost the driver's door window, turn the extreme left dash-face outlet to direct airflow to the upper left.

When a comfortable temperature has been reached, adjust the fan switch setting and temperature control switch as needed to maintain the temperature.

NOTE: To increase the flow of warm air to the floor, close the dash-face outlets.

Air Conditioning Using Fresh Air

IMPORTANT: Operate the air conditioner at least five minutes each month, even during cool weather. This helps prevent drying and cracking of tubing seals, reducing refrigerant leaks in the system. Operate the air conditioner only after the engine compartment is warm, and the interior of the cab is 70°F (21°C) or higher. During cold weather, the heater can be operated at the same time, to prevent discomfort.

If the cab is hot inside, temporarily open the windows to let the hot air out.

Move the air conditioning on/off lever to the off position, and turn the fan switch off before starting the engine.

Start the engine.

Move the air conditioning on/off lever to the on position. Then select fresh or recirculated air with the air source lever.

IMPORTANT: If the outside air is dusty or smoky, set the air source lever at recirculated air and keep the windows and vent closed, to prevent drawing in dust or smoke.

Move the temperature control switch counterclockwise for cool air. In this position, no heat is given off by the heater.

Turn the fan switch to the highest speed. See Fig. 3.37 .

1. Fan Switch
2. Air Selection Switch
3. Temperature Control Switch
4. Air Source Lever at the Fresh Air Position
5. AC On/Off Lever at the On Position

Fig. 3.37, Air Conditioning Settings

As soon as cool air is flowing from the dashboard outlets, close the windows. Adjust the fan switch setting as desired.

If the air from the vents is too cold, move the temperature control switch clockwise for warmer air flow.

IMPORTANT: To prevent the buildup of fumes or odors inside of the cab (for example, from smoking), do not operate the heater and air conditioning system with the air source lever in the recirculation mode for more than 20 minutes.

Fresh Air

Move the air source lever (if equipped) to the fresh air position. See Fig. 3.37 . Move the air selection switch to the desired position.

NOTE: If not equipped with an air source lever, the air source is fresh air.

Move the temperature control switch counterclockwise for no heating, or move it clockwise for heat.

Set the fan switch at the desired speed.