2003 GMC Sierra 1500 Pickup Owner's Manual - Page 486

Electrical System Add-on Electrical Equipment Notice: Don't add anything electrical to your vehicle unless you check with your dealer first. Some electrical equipment can damage your vehicle and the damage wouldn't be covered by your warranty. Some add-on electrical equipment can keep other components from working as they should. Your vehicle has an air bag system. Before attempting to add anything electrical to your vehicle, see Servicing Your Air Bag-Equipped Vehicle on page 1-77. Power Windows and Other Power Options Circuit breakers protect the power windows and other power accessories. When the current load is too heavy, the circuit breaker opens and closes, protecting the circuit until the problem is fixed or goes away. Fuses and Circuit Breakers The wiring circuits in your vehicle are protected from short circuits by a Combination of fuses, circuit breakers and fusible thermal links. This greatly reduces the chance of fires caused by electrical problems. Look at the silver-colored band inside the fuse. If the band is broken or melted, replace the fuse. Be sure you replace a bad fuse with a new one of the identical size and rating. If you ever have a problem on the road and don't have a spare fuse, you can borrow one that has the same amperage. Just pick some feature of your vehicle that you can get along without - like the radio or cigarette lighter - and use its fuse, if it is the correct amperage. Replace it as soon as you can. Windshield Wiper Fuses The windshield wiper motor is protected by an internal circuit breaker and a fuse. If the motor overheats due to heavy snow, etc., the wiper will stop until the motor cools. If the overload is caused by some electrical problem and not snow, etc., be sure to get it fixed. 5-111