For 1990-2009 cars

The red brake warning lamp in the instrument cluster will illuminate to warn the driver of a condition in the brake system, which may result in reduced braking ability. The lamp will illuminate when the parking brake is applied or not fully released, or if the brake fluid level switch is closed. Closed is when the brake fluid is low in the master cylinder reservoir. When the brake fluid level switch is closed, low condition, a brake warning lamp will stay illuminated until the condition has been repaired. Also, some failure modes in the DBC 7 system will illuminate the lamp to let the drivers know the de-coupled dynamic rear proportioning (DDRP) is disabled.