2012 GMC Sierra Owner's Manual - Page 270

8-4 Climate Controls The knob can be positioned between two modes to select a combination of those modes. Select from the following: Climate Control Systems (with Heater Only) With this system the heating and ventilation can be controlled. H (Vent): Air is directed to the instrument panel outlets. ) (Bi-Level): 6 (Floor): Air is divided between the instrument panel and floor outlets. Air is directed to the floor outlets, with some air directed to the windshield, side window, and second row floor outlets. In this mode, the system automatically selects outside air. A. Fan Control B. Temperature Control C. Air Delivery Mode Control Temperature Control: Turn clockwise or counterclockwise to increase or decrease the temperature inside the vehicle. 9 (Fan Control): Turn clockwise or counterclockwise to increase or decrease the fan speed. Turn the knob all the way counterclockwise to turn the front system off. Air Delivery Mode Control: Turn clockwise or counterclockwise to increase or decrease the temperature inside the vehicle. - (Defog): This mode clears the windows of fog or moisture. Air is directed to the windshield, floor outlets, and side window vents.