While driving my 2000 Jimmy (120,000 miles) yesterday as I approached an intersection, the brake pedal went almost to the floor and the brake warning light came on. I managed to limp home and discovered fluid leaking at the left rear wheel. Also, the front section of the master cylinder was almost empty. I topped off the master cylinder and went for a test drive (carefully) hoping the warning light would at least shut off - it didn't. Obviously, I'm going to get the leak repaired, and have the system bled. I have a question about the warning light. Will it go off once the repair is made and the system is properly bled? By the way, the vehicle has the 310 ABS system (black cover).

 

The light should go away after the repairs, if not, then you need to look into your braking system and parking brake system a little further.

The light comes on when your brakes are dangering your stopping ability.