2001 GMC Sierra 1500 Pickup Owner's Manual - Page 202

Your vehicle has air outlets in the center and on the sides of your instrument panel. Ventilation Tips D Keep the hood and front air inlet free of ice, snow or any other obstruction (such as leaves). The heater and defroster will work far better, reducing the chance of fogging the inside of your windows. D When you enter a vehicle in cold weather, turn the fan knob all the way to the right for a few moments before driving. This helps clear the intake ducts of snow and moisture, and reduces the chance of fogging the inside of your windows. objects. This helps air to circulate throughout your vehicle. affect the performance of the heating and air conditioning system. D Keep the air path under the front seats clear of 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 or 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. D The use of hood air deflectors may adversely 3-15