Brake Warning Indicator: Description and Operation

How the Circuit Works
The brake system indicator light comes on to alert the driver that the parking brake is applied, or that the brake fluid level is low. It also comes on as a bulb test when the engine is cranked.

Parking Brake

With the ignition switch in ON (II) or START (III), voltage is applied through fuse 13 to the gauge relay. The gauge relay then applies battery voltage through fuse 55 to the brake system indicator light. When you apply the parking brake, the switch closes and provides a ground for the light, and the light comes on to remind the driver that the parking brake is applied.

Brake Fluid Level

The brake system indicator receives battery voltage through fuse 55 and the gauge relay. If the brake fluid level is low, the brake fluid level switch closes, providing ground to the circuit. The brake system indicator light then comes on, alerting the driver to a low brake fluid level in the master cylinder. (Check brake pad wear before adding fluid.)

Bulb Check

With the ignition switch in ON (II) and the engine not running, the alternator applies a ground signal to the WHT/BLU wire to turn on the brake system indicator light as a bulb check.