2008 GMC Sierra 1500 Pickup Owner's Manual - Page 165

H(Vent): Air is directed to the instrument panel outlets. )(Bi-Level): Air is directed partly 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. Air is directed to the floor outlets, with some to the windshield, side window outlets, and second row floor outlets. In this mode, the system will automatically select outside air. 6(Floor): The recirculation mode cannot be used with floor, defog, or defrost modes. If recirculation is selected with one of those modes, the indicator light flashes three times and then 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. The recirculation mode can be turned off by pressing the outside air button, or by turning off the ignition. -(Defog): See "Defogging and Defrosting" later in this section. @(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 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. ; (Outside Air): Press this button to turn on the outside air mode. When this mode is selected, air from outside the vehicle circulates throughout the vehicle. An indicator light on the button comes on to show that it is activated. The outside air mode can be used with all modes, but it cannot be used with the recirculation mode. 3-29