Principals of Operation

The automatic parking brake release consists of the following components:
^ Release motor
^ Vacuum solenoid
^ Gearshift lever position switch
^ Parking brake warning indicator switch
^ Vacuum hoses and wiring harnesses connecting the various components

When the parking brake is set, and the gearshift lever is moved to "R" or "D", closing the gearshift lever position switch, a circuit is completed, energizing the vacuum solenoid. The solenoid routes engine vacuum to the release motor, releasing the parking brake control. Once the parking brake is released, the parking brake warning indicator switch opens, de-energizing the vacuum solenoid. The vacuum solenoid is energized only when both the parking brake warning indicator switch and the gearshift lever position switch are closed.