Inspection of the Cab

ep3 DM 18.05.005
  1. With the key in the OFF position, check the air-pressure warning system.
  2. Check air governor cut-in and cut-out pressures.
    1. Start the vehicle and ensure the BRAKE AIR lamp goes out and the buzzer silences when pressure reaches approximately 70 psi (483 kPa) in both air reservoirs.
      The air governor should cut out at approximately 120 psi (827 kPa).
    2. Apply the brake pedal several times. The air governor should cut in when pressure in the primary air reservoir (top air gauge) reaches approximately 100 psi (689 kPa).
  3. Check air pressure build-up time.
    1. With the air system fully charged, make one full brake application and note the air pressure reading on the primary air gauge.
    2. Further reduce air pressure using moderate brake applications, then run the vehicle at governed rpm.
    3. Note the time that the pressure reaches the previously noted reading on the primary air gauge, then note the time that the air pressure reaches cut-out pressure.
    4. If it takes longer than 30 seconds to reach cut-out pressure after the primary air gauge passes the previously noted pressure (noted after one full brake application), eliminate any leaks or replace the air compressor before operating the vehicle.
  4. Check air leakage in the system.
    1. With the parking brake applied and the air system fully charged, release the service brakes and shut down the vehicle.
    2. Wait one minute and note the air pressure drop in psi (kPa) per minute from the primary air reservoir.
      If the pressure drop exceeds the limits shown in Table  , eliminate any leaks before operating the vehicle.
  5. Check the air pressure reserve.
    With the vehicle still off, make one full brake application and observe the pressure drop on the primary air gauge. If pressure drops more than 25 psi (172 kPa), eliminate any leaks before operating the vehicle.

    Table 1, Maximum Allowable Air Leakage

    Description

    Pressure Drop:

    psi (kPa) Per Minute

    Released

    Applied

    Truck or Tractor Only

    2 (14)

    3 (21)

    Truck or Tractor w/Single Trailer

    3 (21)

    4 (28)

    Truck or Tractor w/Two Trailers

    5 (35)

    6 (42)

      Table 1, Maximum Allowable Air Leakage

      1. Warning: When cleaning windshields and windows, always stand on the ground or on a secure ladder or platform. Use a long-handled window cleaner.

      Do not use the cab steps, tires, fenders, fuel tanks, engine, or under-hood components to access the windshield or windows. Doing so could cause a fall and result in a severe injury.

      Notice: Do not use the turning vanes as handholds. Doing so could cause damage to the vehicle.

    1. Inspect the mirrors, window glass, and windshield for cracks or other damage.
    2. Ensure that the horn, windshield wipers, and windshield washers are operating properly. These devices must be in good working order for safe vehicle operation.
    3. Turn the fan on and ensure the cab heater and window defroster are operating properly.
    4. Check the operation of all interior lights.
      1. Turn on the headlamps and leave them on.
      2. Ensure ICU screens illuminate.
      3. Ensure all equipped driver control switches illuminate and verify the interior cab lights controlled by these switches illuminate.
      4. Ensure both turn signal indicators illuminate when the turn signal switch is activated.

        1. Clearance (Marker) Lamps

        2. Identification Lamps

        3. Turn Signal

        4. DRL/Accent Lamps

        5. Headlamp, Low Beam

        6. Headlamp, High Beam

        7. Side Marker Lamp

        8. Stop Lamps (Tail Lights), Turn Signals, Back-Up Lamp

        Fig. 1, Exterior Lights

    5. Check the operation of all exterior lamps. See Fig. .
      Use the lamp check button on the key fob, shown in Fig. , or, if equipped, the LIGHT TEST switch on the dash as shown in Fig. .
      If neither are available, manually check the operation of all exterior lamps.

      1. Door Lock

      2. Door Unlock

      3. Lamp Check

      Fig. 2, Key Fob

      Fig. 3, Pretrip Light Test Switch

    6. To check the exterior lamps using the key fob lamp check button or the dash LIGHT TEST switch:
      1. Make sure the parking brake is set.

        Note: Vehicle factory settings will have groups of lamps activate sequentially up to 100 times or until manually stopped.
        1. Press either the LIGHT TEST switch or lamp check button to begin the pre-trip light inspection. If equipped, groups of lamps will cycle on and off in the following sequence:

          • Group 1: Always ON: marker lamps, clearance lamps, tail lamps, licence plate lamp

          • Group 2: Low beam headlamps

          • Group 3: High beam headlamps and stop lamps

          • Group 4: Backup lamps and daytime running lamps

          • Group 5: Front and rear fog lamps

          • Group 6: Turn signals and utility lamps

          Note: LED accent lighting turns off when the high beam headlamps turn on.
          1. Walk around the truck and check that the lamps are working properly.
          2. Verify that all exterior lights and reflectors are clean and intact.
          3. The pretrip light inspection can be stopped by:

            • releasing the parking brake;

            • pressing either the lamp check button on the key fob or the LIGHT TEST switch on the dash.

        2. To check exterior lamps manually:
          1. Turn the keyswitch to the ON or ACC ON position.
          2. Make certain the parking brake is set.
          3. Activate the high-beam headlamps and hazard warning lamps.
          4. Exit the cab and check that all exterior lamps and reflectors are clean and intact.
          5. Check that the brake lamps, tail lamps, headlamps, turn signals, marker lamps, identification lamps, and clearance lamps are working properly.

          3. Warning: Inspect and maintain seat belts. When any part of a seat belt system needs replacement, the entire seat belt must be replaced, both retractor and buckle side. Any time a vehicle is involved in an accident, and the seat belt system was in use, the entire vehicle seat belt system must be replaced before operating the vehicle. Do not attempt to modify the seat belt system; doing so could change the effectiveness of the system. Failure to replace worn or damaged seat belts, or making any modifications to the system, may result in personal injury or death.

        3. Inspect the seat belts and tether belts.
          1. Check the web for fraying, cuts, extreme dirt and dust, or for severe fading from exposure to sunlight, especially near the buckle latch plate and in the D-loop guide area.
          2. Check operation of the buckle, latch, web retractor, and upper seat belt mount on the door pillar. Check all visible components for wear or damage.
          3. Check the seat belt and tether belt connection points and tighten any that are loose.
        4. Adjust the rearview and down view mirrors as necessary.
        5. Test the service brakes.
          1. With the key ON and air system fully charged, set the parking brake.
          2. Put the vehicle in the lowest gear and gently attempt to move it forward. The vehicle should not move.
            If the vehicle moves, the parking brakes are not operating correctly and must be repaired before the vehicle is operated.
        6. Test the backup beep.
          1. Release the parking brake.
          2. Move the vehicle slightly backward to ensure that the backup beep is audible.
        7. Press the ’Test’ button on the combustible gas detection system control panel.
          The system will illuminate the ’Trace Gas,’ ’Significant,’ and all other sensor LEDs, and sound the piezo buzzer. Watch to see that all lights illuminate or flash and listen to verify the buzzer alarm goes off.
          If the self-diagnostic test fails, have the gas detection system repaired before putting the vehicle into service.
        Note:
        Parent topic: Daily Pre-Trip Inspections and Maintenance
        Document Number: 0000087044
        Manual Publication Date: 2024-03-21
        Topic Publication Date: 2025-02-13