Brake Light Switch: Description and Operation

Typical Brake Pedal Position Switch:

The Brake On-Off (BOO) switch is mounted at the brake pedal assembly. Closing of the switch contacts when the brakes are APPLIED, signals the Engine Control Assembly (ECA) to modify the operation of the torque converter clutch (if equipped), A/C compressor (if equipped), and idle speed and air/fuel ratio during periods of decel and idle.