Brake Light Switch: Description and Operation

The brake lamp switch consists of multiple switch contacts either normally open or closed. The switch contacts provide brake pedal status to the various controllers. The primary function of the switch is to illuminate the brake lamps. The brake lamp switch is adjustable and mounted on the brake pedal mounting bracket under the instrument panel.

Vehicles equipped with the speed control option use a multiple function brake lamp switch. The PCM monitors the state of the brake lamp switch. Refer to the Brake section for more information on brake lamp switch service and adjustment procedures.

The primary function of the brake switch is to turn on the brake lamps during braking. The switch is also used to send signals to components that must know when the brakes are applied, such as the Powertrain Control Module (PCM), which uses the signal to cancel speed control. The Controller Antilock Brake (CAB) uses the brake switch signal to monitor brake pedal application. When the normally closed switch contacts open, the CAB receives the brake applied signal. The CAB then monitors the ABS system to anticipate the need for a ABS stop.