2003 GMC Envoy Owner's Manual - Page 386

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 1-59. Headlamps The headlamp wiring is protected by four fuses. An electrical overload will cause a lamp to go on and off. if this happens, have your headiamp wiring checked right away. Windshield Wiper Fuses The windshield wiper motor is protected by a circuit breaker and a fuse. If the motor overheats due to heavy snow or ice, the wiper will stop until the motor cools. If the overload is caused by some electrical problem, be sure to get it fixed. 5-91