1995 GMC Sonoma Owner's Manual - Page 105

A CAUTION: Your brake system may not be working properly if the brake system warning lightis on. Driving with the brake system If warning light on can lead to an accident. the light is still on after you've pulledoff the road and stopped carefully, have the vehicle towedfor service. The brake system warning light will also come on when you set your parking brake, and it will stay on if your parking brake doesn't release fully. If it stays on after your parking brake is fully released, it means you have a brake problem. Anti-Lock Brake System Warning Light(Option) If your vehicle has four-wheel anti-lock brakes, it will have this yellow light. With the anti-lock brake system, this lightwill come on when you start your engine and may stay on for several seconds. That's normal. If the light doesn't come on, have it fixed so it will be ready to warn you if there is a problem. If the light stays on, or comes when you're driving, your vehicle needs on service. If the regular brake system warning light isn't on,you still have brakes, but you don't have anti-lock brakes. If the regular brake system warning light is also on, you don't have anti-lock brakes and there's a problem with your regular brakes. See "Brake System Warning Light" earlier in this part. 2-59