Pre-Trip Brake Check Switch

This vehicle may be equipped with the optional pre-trip brake switch, shown in Fig. . This switch is intended to simplify the daily process of inspecting the tractor and trailer for air leaks, especially when inspecting the vehicle alone. By engaging this switch, the service brakes and the park brakes are applied simultaneously so the leaks at the wheels ends can be inspected without having to pump the brakes manually.

Pre-trip brake check switch

Fig. 1, Pre-Trip Brake Switch

To operate the switch, the following interlocks must be met:

• The park brake must be engaged and the truck must be parked.

• The engine must be on.

• The air pressure must meet the required threshold of 100 psi (690 kPa).

• The trailer park brake must be released.

Complete the inspection as follows:

1. Meet the interlocks: engage the park brake, release the trailer park brake, and ensure the engine is on and the air pressure meets the minimum threshold.

   Note: If any of the interlocks are not met, a pop-up displays on the instrument cluster describing which interlock is missing.

2. Press the pre-trip brake check switch to turn on the feature. The switch illuminates when the feature is active.

3. Exit the vehicle and perform the visual and auditory inspection of the brakes.

4. Once the brakes are inspected for leaks, turn the switch off and proceed with the remaining inspections and maintenance.

If the pre-trip brake switch is engaged for longer than 30 minutes, a pop-up titled ‘brake check still on’ appears in the instrument cluster, as a reminder to turn off the feature.