2000 GMC Sierra 1500 Pickup Owner's Manual - Page 175

yellowblue If your vehicle is equipped with heated outside mirrors, the rear window defogger button will also activate the heated outside mirrors. Do not attach a temporary vehicle license, tape or decals across the defogger grid on the rear window. Outside air will also enter the vehicle when the heater or the air conditioning fan is running, unless you have the RECIRCULATION button pushed in. For more information on the RECIRCULATION button, see "Air Conditioning" earlier in this section. Your vehicle has air outlets in the center and on the sides of your instrument panel. NOTICE: Don't use a razor blade or something else sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs wouldn't be covered by your warranty. Ventilation System For mild outside temperatures when little heating or cooling is needed, use VENT to direct outside air through your vehicle. Air will flow through the instrument panel outlets. Your vehicle's ventilation system supplies outside air to the inside of your vehicle when it is moving. With the side windows closed, air will flow into the front air inlet grilles, through the vehicle, and out the air exhaust valves. You can turn the outlets from side-to-side or up and down to direct the flow of air. The left driver and passenger outlets on vehicles equipped with air conditioning have shut off knobs. Turn the knob to the left to shut off air flow, to the right to allow air flow. When you close an outlet, it will increase the flow of air coming out of any outlets that are open. The center outlet does not completely shut off airflow. 3-7