2010 GMC Acadia Owner's Manual - Page 247

Climate Controls Using recirculation for long periods of time could cause the air inside of the vehicle to become too dry. To prevent this from happening, after the inside of the vehicle has cooled, turn the recirculation mode off. 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. The recirculation mode cannot be used with floor, defrost, or defogging modes. If recirculation is selected in these modes, the indicator flashes three times and turns off. The air conditioning also comes on when this mode is activated unless the outside air temperature is less than 4°C (40°F). 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 (Rear Climate Control): 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. 8-3 < (Rear Window Defogger): Press to turn the rear window defogger on or off. The rear window defogger stays on for about 10 minutes, before automatically turning off. The defogger will also turn 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 < 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. @ (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 The rear window defogger uses a warming grid to remove fog from the rear window.