Brake Warning Lamp Circuit Operation

The Brake Warning Indicator lamp is used to alert the operator of a problem with the vehicle's braking system. The lamp illuminates when the ignition switch is turned to START position to perform a self-check.

There are two switches used in this system and they are wired in parallel. A parking brake switch, located on the parking brake mechanism illuminates the lamp if the normally open switch is closed. This switch is case-grounded.

The other switch used is the Brake Warning lamp switch. This switch is normally open. When the brake system pressure is below a predetermined level, the switch closes and completes a path to ground from the G9 circuit at the cluster through the switch, then to the left headlamp ground.

If the vehicle is built for use in Canada the parking brake switch is used for the Daytime Running Lamp Module. Daytime Running Lamp