Trailer Air Supply Valve

m2 dm 04.07.002

The red octagonal-shaped knob (Fig.) on the auxiliary dash panel operates the trailer air supply valve. After the vehicle and its air hoses are connected to a trailer, and the pressure in the air system is at least 65 psi (448 kPa), the red knob must be pushed in (and 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, the red knob must be pulled out.

  1. Trailer Air Supply Valve (red knob)

  2. Parking Brake Control Valve (yellow knob)

Fig. 1, Brake Valve Control Knobs

See General Information under the heading "Dual Air Brake System" for further information about the trailer air supply valve.

Note:
Parent topic: Braking
Document Number: 0000117514
Manual Publication Date: 2025-02-11
Topic Publication Date: 2024-05-09