Brake Warning System Description and Operation

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

The brake warning indicator is located in the instrument cluster. The brake warning indicator illuminates in order to warn the driver of conditions in the brake system which may result in reduced braking capability.

The following conditions will turn on the brake warning indicator:

The ignition switch is in the ON position. The brake warning indicator illuminates When the key is turned ON for a bulb check in order to notify the driver that the brake warning circuit is operating properly.
The brake indicator receives ignition voltage through the IG fuse. When the ignition switch is in the ON position, a path to ground is provided to the brake indicator through the ignition switch to G200. With power and ground provided, the indicator illuminates for 3 seconds.
The park brake is applied or not fully released.
When the parking brake is applied, the switch on the park brake lever closes, sending a ground signal to the daytime running lamps (DRL) control module. The DRL control module controls the ground for the brake indicator.
The brake fluid level is low.
If the brake fluid level drops in the master cylinder reservoir, the brake fluid level switch closes, providing a path to G104 for the brake indicator.