Brake Pressure Applied Switch

NOTE: BPA switch may also be referred to as deactivator switch or redundant speed control deactivator switch.

The Brake Pressure Applied (BPA) switch is a normally closed hydraulically controlled pressure switch that is located on the brake master cylinder. BPA switch senses brake fluid pressure and provides a back up to the brakelight switch signal to deactivate cruise (speed) control. The BPA switch is independent (mechanically and electrically) from the brakelight switch. BPA switch actuates after the brakelight switch is actuated.

All vehicles with hydraulic brakes have a single BPA switch. Normally, a brakes-applied signal from BPP switch will disengage speed control. If BPP switch signal is lost, BPA switch will supply brakes-applied signal to speed control servo.