Brake Light Switch: Description and Operation

The Brake Switch is integrated into the BAS Solenoid Valve (2). The Brake Switch/BAS solenoid valve (2) cannot be serviced. The power brake booster must be replaced in the event of a Brake Switch/BAS solenoid valve failure.

The Brake Lamp Switch is integrated with the BAS Solenoid Valve. As the brake pedal is applied, the brake switch is activated and a signal is sent to the CAB module. The CAB then grounds the coil side of the brake lamp relay. This action completes the brake lamp circuit, and allows the brake lamps and Center High Mounted Stop Lamp to illuminate. When the brake pedal is released, the plunger returns to its rested position, and the brake lamp relay is de-energized. As the relay is de-energized, the brake lamps are again returned to their off state.