Other Dash-Mounted Controls
Windshield-Fan Switches, Optional
Ceiling-mounted defogger fans are operated by LOW/OFF/HIGH toggle switches located in the base of the fan.
Cigarette Lighter
Push in the lighter to heat the element. The lighter will stay in and will automatically pop out when the element is hot.
CB Radio Connections
An antenna connection and positive (+) and negative (–) power connections are provided for a CB radio.
Suspension Dump Switch
Notice: Do not operate the vehicle over uneven ground such as ramps, speed bumps, curbs, etc. with the air springs deflated. Doing this may lead to air bag separation from the piston, preventing the suspension air springs from reinflating.
Notice: Never exhaust air from the suspension while driving. When the air is exhausted, the suspension will not absorb road shocks, and components may be damaged.
The suspension dump switch is a two-position guarded rocker switch (Fig.). It 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.
Fig. 1, Suspension Dump Switch
To lower the rear of the vehicle quickly, press the upper half of the rocker momentarily (at the LED). To raise the suspension to its normal height, press the upper half of the rocker again.
When the panel lights are on, the tractor icon is backlit in green.
Important: The suspension dump switch is guarded to prevent unintentional switch activation. This switch does not have a diagnostic blink function when inactive.
When the suspension dump switch is pressed, three responses are possible: a normal response, a slow response, and an abnormal response.
Normal Response: The LED in the switch blinks while the suspension is deflating or filling. When it is completely deflated, the LED comes on steady and stays illuminated. In normal operation, the suspension may dump or fill so quickly that the blinking of the switch is barely noticeable.
If operation of the switch is not possible for any reason (vehicle is moving faster than 5 mph, ignition is turned off, etc.), the LED will stop blinking and turn off.
Slow Response: If operation of the switch is slowed for any reason (by cold weather, low air pressure, etc.), the switch will continue to blink until the suspension completes a dump or fill. As in the normal response, the LED comes on steady and stays illuminated when the suspension if fully deflated.
Abnormal Response: If the LED blinks for more than 10 seconds, the suspension dump mechanism may not be operating properly. Bring the vehicle to an authorized Freightliner service facility for testing.
If the ignition is turned off while the vehicle is in dump mode, the power to the dump solenoid is cut off to prevent battery drain, and the suspension system will autofill the rear air springs. The suspension will also autofill if the vehicle is operated with the suspension dumped, and the speed is over 5 mph (e.g. -- driver forgot to inflate the bags or there was a system failure).
Suspension Autofill Override Valve
The suspension autofill override option is a dash air valve, that keeps the suspension deflated when the ignition is turned off. To operate it, turn off the ignition then push the override valve knob. See Fig.. When the ignition is turned on, the override valve will release automatically, and the suspension will autofill. The suspension dump switch will then operate normally as described previously.
