2010 GMC Savana 2500 Cargo Owner's Manual - Page 174

The vehicle can be only driven for a short time with the reading in either warning zone. If it must be driven, turn off all unnecessary accessories. Readings in either warning zone indicate a possible problem in the electrical system. Have the vehicle serviced as soon as possible. When the ignition is on, the brake system warning light also comes on when the parking brake is set. See Parking Brake on page 3-35 for more information. The light stays on if the parking brake does not fully release. If it stays on after the parking brake is fully released, it means the vehicle has a brake problem. If the light comes on while driving, pull off the road and stop carefully. The pedal might be harder to push, or the pedal might go closer to the floor. It could take longer to stop. If the light is still on, have the vehicle towed for service. See Towing Your Vehicle on page 5-22. Brake System Warning Light The vehicle's hydraulic brake system is divided into two parts. If one part is not working, the other part can still work and stop the vehicle. For good braking, both need to work. If the warning light comes on, there could be a brake problem. Have the brake system inspected right away. { WARNING: The brake system might not be working properly if the brake system warning light is on. Driving with the brake system warning light on can lead to a crash. If the light is still on after the vehicle has been pulled off the road and carefully stopped, have the vehicle towed for service. United States Canada This light should come on briefly when ignition key is turned to ON/RUN. If it does not come on, have it fixed so it will be ready to warn if there is a problem. 4-28