2010 Chevrolet Avalanche Owner's Manual - Page 226

: (Outside Air): Press to turn the outside air mode on. An indicator light comes on to show that outside air is on. Air from outside the vehicle is circulated throughout the vehicle. The outside air mode can be used with all modes, but it cannot be used with the recirculation mode. Pressing this button again will cancel the recirculation mode. ? (Recirculation): Press to turn the recirculation mode on or off. An indicator light comes on to show that recirculation is on. This mode recirculates and helps to quickly cool the air inside the vehicle. It can be used to help prevent outside air and odors from entering the vehicle. The recirculation mode cannot be used with floor, defrost, or defogging modes. If recirculation is selected while in one of those modes, the indicator flashes three times and turns off. The air conditioning compressor will also come on when this mode is activated. While in recirculation mode the windows may fog when the weather is cold and damp. To clear the fog, select either the defog or defrost mode and increase the fan speed. The recirculation mode can also be turned off by turning off the engine. Rear Window Defogger The rear window defogger uses a warming grid to remove fog from the rear window. < (Rear Window Defogger): Press this button on the right knob to turn the rear window defogger on or off. The system automatically turns off several minutes after it has been activated. The defogger can also be turned off by turning off the engine. Do not drive the vehicle until all the windows are clear. For vehicles with heated outside rearview mirrors, the mirrors will heat to help clear fog or frost from the surface of the mirror when the rear window defog button is pressed. Notice: Do not use anything sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs would not be covered by the vehicle warranty. Do not attach a temporary vehicle license, tape, a decal or anything similar to the defogger grid. 4-18