How Do Heated Outside Mirrors Work on a GMC?by Contributor
Heated Mirror Benefits
Front window defrosters have been around for almost as long insides of automobiles have been heated. Rear window defrosters have been around for decades. Eventually, someone thought it would be nice to attach heated mirrors to cars. It did not take long to figure out how to do this, and people can buy heated mirrors for their cars or trucks. Some GMC vehicles have these heated mirrors. Most heated mirrors attach to the electric elements that control a car's rear defroster. When the rear defroster is turned on, the heating elements in the mirrors should be active. Keeping ice and fog off side view mirrors allows a driver to more easily see vehicles and other dangers behind him when weather conditions are inclement.
How Heated Mirrors Keep Themselves Clear
Heated mirrors on GMC vehicles keep themselves free from fog and ice the same way the defroster keeps the windshield clear. A small amount of heat is applied to the glass surface of the side mirrors. Electrical elements in the mirrors heat the surface of the glass. The heat evaporates moisture on the glass' surface and melts any ice that has built up. Electrical wires in the door panels attached to the side view mirrors allow the heating element to draw power from a GMC car or truck's battery.
GMC Heated Mirror Controls
On cars that come with heated mirrors as standard equipment, whether or not GMC manufactures the vehicle, the heated mirrors may have a separate control panel on the driver's side of the car or truck. If this control panel is not present, the driver turns on the mirrors whenever he turns on the rear defroster. A trained mechanic can easily install these mirrors. Skilled do-it-yourself auto-enthusiasts may be able to place heated mirrors on their GMC car as well, provided they carefully follow the instructions that come with the package. Having them installed by a dealer keeps most of the warranties that exist on newer GMC cars or trucks intact.
Specific Issue With GMC Truck Heated Mirrors
The mirrors occasionally will heat unevenly. This affects the passenger side of GM trucks most frequently. Replacing the glass mirror usually fixes this problem. (If the mirror is not the problem, it is most likely that the heating element behind the glass surface has gone bad.)