Air-Actuated Uncoupling

sdp dm 17.03.002

A dash-mounted kingpin release switch (if so equipped) may be used to uncouple the trailer. See Fig..

Fig. 1, Kingpin Release Switch

Note:  In the event of an air system failure, air-actuated kingpins can be manually released following the instructions for manual uncoupling. If there is an issue, see Fig. should appear on the driver’s display screen.

Fig. 2, Kingpin Release Not Confirmed Popup, ICUC

Warning: Once the kingpin release switch has been pushed, the kingpin lock is released. The vehicle MUST NOT be driven with the trailer until the trailer has been uncoupled and coupled again. Failure to do so may result in separation of the trailer from the tractor, possibly causing serious personal injury or death.

Preparing the Trailer for Uncoupling

Before using the air valve to unlock a fifth wheel kingpin, prepare the trailer as follows.

  1. Slowly back the tractor tightly against the trailer to relieve pressure on the fifth wheel locks.

  2. Apply the tractor and trailer parking brakes.

  3. Chock the trailer rear wheels.

  4. Lower the trailer landing gear until the weight is removed from the fifth wheel.

  5. Disconnect the tractor-to-trailer air lines and electrical cable. Plug the air lines to prevent dirt or foreign material from entering the lines.

Air-Activated Kingpin Unlock

Note:  The kingpin release will not activate if the vehicle is moving, the parking brake is not set, or if the switch is pushed for less than 3 seconds. Unless all of these conditions are met, the trailer will not be uncoupled.

If the kingpin release switch is pressed for less than 3 seconds, see Fig. will appear on the driver display. Press the back arrow to dismiss the popup.

Fig. 3, Kingpin Release Not Activated Popup, ICUC

  1. Verify that both the yellow parking-brake and red trailer-air supply knobs are out, the tractor and trailer parking brakes are set, and that the trailer is prepared for uncoupling.

  2. Push and hold the kingpin release switch, shown in Fig., for a minimum of 3 seconds. The system will apply air for 20 to 30 seconds to ensure the kingpin unlocks. When the kingpin is unlocked, a notification is displayed as shown in Fig..

  3. Release the tractor parking brake.

  4. Drive out from under the trailer.

Note:
Parent topic: Fifth Wheel Uncoupling
Document Number: 0000110761
Manual Publication Date: 2024-09-03
Topic Publication Date: 2024-05-02