Brake Light Switch: Description and Operation

The plunger type brake lamp switch is mounted on a bracket attached to the brake pedal support. The switch can be adjusted when necessary.

When the brake light switch is activated, the Powertrain Control Module (PCM) receives an input indicating that the brakes are being applied. After receiving this input, the PCM maintains idle speed to a scheduled rpm through control of the Idle Air Control (IAC) motor. The brake switch input is also used to disable vent and vacuum solenoid output signals to the speed control servo.

The brake lamp switch is also used to operate the brake lamps, as well as to provide inputs to the Powertrain Control Module (PCM) and, the Controller Anti-lock Brake (CAB).