Release the lever next to the driver seat in order to release the park brake. The park brake control module (PBCM) turns on the park brake pump motor in order to supply hydraulic pressure to the park brake actuator. The park brake actuator has a large spring on the inside that applies the park brake. When running, the park brake pump motor supplies hydraulic pressure behind a piston in the actuator which overcomes opposing spring tension. The actuator moves when the spring compresses. This movement transfers over to the park brake through the park brake cable.

The pump shuts off after the park brake is released. The park brake control module then monitors the system pressure. The park brake control module turns the pump on in order to maintain the system pressure if the pressure drops too low.

The park brake solenoid is de-energized when the dash park brake switch is pulled out. This allows the fluid to dump back into the hydraulic reservoir.The spring tension in the actuator moves against the piston as the pressure drops. The actuator applies the park brake through the movement of the park brake cable.