Brake Lamp: Description and Operation

The brake (or stop) lamps and the Center High Mounted Stop Lamp (CHMSL) each have a path to ground at all times through a takeout and eyelet terminal of the body wire harness that is secured by a ground screw to the left inner D-pillar behind the quarter trim panel. The brake lamps and CHMSL receive battery voltage on the brake lamp switch feed circuit when the brake lamp switch is closed by the brake pedal arm. The CHMSL is connected to a hard wired output from the brake lamp switch, while the brake lamps are controlled by an output from the Front Control Module (FCM) based upon an input from the brake lamp switch.