Brake Light Switch: Description and Operation

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

The brake lamp switch is used to for the brake lamp, speed control and brake sensor circuits.

BRAKE SWITCH - PCM INPUT
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.