Three problems related to brake light on have been reported for the 2001 GMC Sierra. The most recently reported issues are listed below.
The first day I noticed that the brake pedal went closer to the floor before the brakes activated. The second day the pedal nearly touched the floor and then the brake warning light came on. I took the vehicle to my neighborhood indy tire center where they quickly determined brake line failure near the left rear wheel. The brake line had rusted completely causing a hole and rapid loss of brake fluid. A new teflon coated main brake line and fittings was installed along with new brake fluid. Other brake lines were examine and found to be rusted but not compromised. The total cost of repair was $461. 38.
Failure of abs module caused abs light and red service brake lights to come on. Replacing both front hub bearings (including both front abs sensors and wiring) and repairing the ground strap on the frame for the abs system did not fix the problem. Service brake system has new calipers ,rotors,and pads and a full inspection revealed no problems or failures. Abs module is still on vehicle but will be replaced next.
Abs brake system is not working correctly. Tried to call gm, and they will not return the calls. The brake light also comes on. Car vibrates when applying the brakes.