2008 GMC Acadia Owner's Manual - Page 174

The air delivery mode setting remains displayed, the word AUTO is no longer displayed, and the AUTO button indicator light turns off. @ (Recirculation): Press this button to turn the recirculation mode on. When the button is pressed, an indicator light comes on. This mode keeps outside air from entering the vehicle. It can be used to reduce outside air and prevent odors from entering your vehicle. Recirculation also helps to quickly cool the warmer air inside your vehicle. The recirculation mode cannot be used with floor, defrost, or defogging modes. If you try to select recirculation in one of those 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 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. Press the button again to turn off the recirculation mode. It automatically turns off when the engine is turned off and must be re-selected when the engine is turned on again. H (Vent): This setting delivers air to the instrument panel outlets. This mode directs air to the instrument panel outlets and to the floor outlets. A little air is directed towards the windshield and side window outlets. Cooler air is directed to the upper outlets and warmer air to the floor outlets. ) (Bi-Level): 6 (Floor): This mode directs most of the air to the floor outlets, with some of the air directed to the windshield, side window outlets, and second row floor outlets. In this mode, the system automatically selects outside air. Recirculation cannot be selected in floor mode. - (Defog): See "Defogging and Defrosting" later in this section. 3-32