2010 GMC Acadia Owner's Manual - Page 252

8-8 Climate Controls The recirculation mode cannot be used with floor, defog, or defrosting modes. If recirculation is selected in these modes, the indicator flashes three times and turns off. The air conditioning compressor also comes on when this mode is activated. While in recirculation mode the windows can fog when the weather is cold and damp. To clear the fog, select either the defog or defrost mode and increase the fan speed. REAR: Press to turn the rear heating and air conditioning on or off. See Rear Climate Control System (Rear Climate Control Only) on page 8‑10 or Rear Climate Control System (Rear Climate with Rear Seat Audio) on page 8‑11. On hot days, open the windows briefly to let hot inside air escape. This helps reduce the time it takes for the interior of the vehicle to cool down. The air conditioning system removes moisture from the air, so water might drip under the vehicle while idling or after turning off the engine. This is normal. Rear Window Defogger The rear window defogger uses a warming grid to remove fog from the rear window. @ (Recirculation): Press to turn the recirculation mode on or off. An indicator light comes on when recirculation is on. When the engine is turned off, the recirculation mode automatically turns off and must be re‐selected when the engine is turned on again. This mode recirculates and helps to quickly cool the air inside the vehicle. It can be used to prevent outside air and odors from entering the vehicle. < (Rear Window Defogger): Press to turn the rear window defogger on or off. The rear window defogger stays on for about 10 minutes, before turning off. The defogger also turns off when the engine is turned off. Do not drive the vehicle until all the windows are clear. For vehicles with heated outside rearview mirrors, fog or frost is cleared from the surface of the mirror when the rear window defog button is pressed. 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.