2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 253

Outlet Adjustment Use the air outlets located in the center and on the side of the instrument panel to direct the airflow. Use the thumbwheels near the air outlets to open or close off the airflow. Warning Lights, Gauges, and Indicators Warning lights and gauges can signal that something is wrong before it becomes serious enough to cause an expensive repair or replacement. Paying attention to the warning lights and gauges could prevent injury. Warning lights come on when there might be or there is a problem with one of the vehicle's functions. Some warning lights come on briefly when the engine is started to indicate they are working. Gauges can indicate when there might be or there is a problem with one of the vehicle's functions. Often gauges and warning lights work together to indicate a problem with the vehicle. When one of the warning lights comes on and stays on while driving, or when one of the gauges shows there could be a problem, check the section that explains what to do. Follow this manual's advice. Waiting to do repairs can be costly and even dangerous. Operation Tips . Clear away any ice, snow, or leaves from air inlets at the base of the windshield that could block the flow of air into the vehicle. Keep the path under the front seats clear of objects to help circulate the air inside of the vehicle more effectively. Use of non‐GM approved hood deflectors can adversely affect the performance of the system. Check with your dealer before adding equipment to the outside of the vehicle. . . 4-29