To release the electric/auto park brake, turn the ignition switch to ON and move the transmission range (TR) shift lever from the PARK position. This opens a section of the park/neutral position and backup lamps switch. That allows relay contacts to close providing power to the release circuit.

Apply the parking brake by one of three methods:

Any of these actions de-energizes the parking brake release system which allows the actuator to apply the parking brake.

The AUTO PARK indicator lamp turns on when the system pressure is less than 3 100 kPa (450 psi) or when the electric/hydraulic pump motor is running because the pump motor switch is closed. The pressure pump motor switch and the pressure indicator switch supply B+ to the circuit for lamp operation. The hydraulic pressure involved in releasing the parking brake causes the switches to open the circuit and turns the lamp off. The lamp will light briefly each time the pump runs for pressure maintenance.