Is that warning light red or yellow? If it's red, check the brake fluid level in the reservoir. If it's real low, just add a little clean brake fluid from a sealed container. Do not fill it to the top and be absolutely certain no hint of a petroleum product like engine oil, power steering fluid, or transmission fluid gets in there. Low brake fluid typically means the front disc brake pads are near the end of their life and a brake system inspection is needed. Brake fluid that continually goes down after you keep adding means there's a leak that must be addressed right away.
If the warning light is yellow, that is for the anti-lock brakes. There will be a diagnostic fault code in the computer related to the cause of the problem. Most commonly on GMs that will have something to do with a wheel speed sensor. On the trucks that typically is due to rust buildup between the sensor and hub it's mounted to.
Friday, October 18th, 2013 AT 10:52 AM