1998 GMC Safari Owner's Manual - Page 144

You can only drivefor a short time with the readings in either warning zone.If you must drive, 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. BRAKE This light should come on briefly when you turn the ignition key to RUN. If it doesn't come on then, have it fixedso it will be ready to warn you if there's a problem. Brake System Warning Light When the ignition is the brake system warning light on, will come onwhen you set your parking brake. The light will stay on if your parking brake doesn't release fully. If it stays on after your parking brake fully released,it is means you have a brake problem. Your vehicle's hydraulic brake system is divided into two parts. If one part isn't working, the other part can still work and stop you. For good braking, though, you need both parts working well. If the light comes on while you are driving, off the pull road and stop carefully. You may notice that the pedal is harder to push. Or, the pedal may go closer to the floor. It may take longer to stop. the light isstill on, havethe If vehicle towed for service. (See "Towing Your Vehicle" in the Index.) If the warning light comes on, there could be a brake problem. Have your brake system inspected right away. Your brake system may not be working properly if the brake system warning lighton. Driving is with the brake system warning light on can lead to an accident. If the light on after you've is still pulled off the road and stopped carefully, have the vehicle towed for service.