2011 Chevrolet Silverado 1500 Regular Cab Owner's Manual - Page 283

Climate Controls 8-9 ; (Outside Air): Press to turn the outside air mode on. An indicator light on the button comes on to show that outside is on. When selected, air from outside the vehicle circulates throughout the vehicle. The recirculation mode cannot be used with the outside air mode. Notice: Do not use a razor blade or sharp object to clear the inside rear window. Do not adhere anything to the defogger grid lines in the rear glass. These actions may damage the rear defogger. Repairs would not be covered by your warranty. Heated Mirror: For vehicles with heated outside rearview mirrors, the mirrors heat to help clear fog or frost from the surface of the mirror when the rear window defog button is pressed. See Power Mirrors on page 2‑15. Sensors Rear Window Defogger The rear window defogger uses a warming grid to remove fog from the rear window. 1 (Rear Window Defogger): For vehicles with this feature, press to turn the defogger on or off. It automatically turns off several minutes after it has been activated. The defogger can also be turned off by turning the engine off. Do not drive the vehicle until all windows are clear. The solar sensor, located in the defrost grille in the middle of the instrument panel, monitors the solar heat. Do not cover the solar sensor or the system will not work properly.