2008 GMC Acadia Owner's Manual - Page 169

Airflow Mode Control: Turn the right knob clockwise or counterclockwise to direct the airflow inside of the vehicle. To change the current mode, select one of the following: H (Vent): This mode keeps outside air from entering the vehicle. It can be used to reduce the outside air and odors entering the vehicle. Recirculation may also help cool the air inside the vehicle more quickly once the temperature inside the vehicle is less than the outside temperature. The recirculation mode can be turned off in vent and bi-level modes by pressing the button again. Recirculation mode automatically turns off when the engine is turned off and must be re-selected when the engine is turned on again. 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 unless the outside air temperature is less than 40°F (4°C). 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. This mode directs air to the instrument panel outlets. ) (Bi-Level): This mode directs about half of the air to the instrument panel outlets and half 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. 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 when in Floor Mode. The right knob can also be used to select defog or defrost mode. For more information, see "Defogging and Defrosting" later in this section. By positioning the right knob between two modes, a combination of those two modes is selected. Press this button to turn the recirculation mode on or off. The indicator light on the button turns on when this mode is selected. 6 (Floor): @ (Recirculation): #(Air Conditioning): Press this button on the left knob to turn the air conditioning system on or off. When A/C is pressed, an indicator light comes on to show that the air conditioning has been activated. The air conditioning compressor does not operate when outside temperatures fall below 40°F (4°C). The indicator light flashes three times and turns off when outside conditions affect air conditioning operation. This is normal. 3-27