2002 Pontiac Aztek Owner's Manual - Page 200

(Floor): This setting brings in most of the air through the floor ducts. This setting is also used to send air to the rear of the vehicle. Keep the area under the front seats free of objects that could obstruct airflow to the rear of the vehicle. (Defog): This setting directs air to the windshield and through the floor ducts. Use this mode during cold or inclement weather because of your vehicle's larger windshield area. (Defrost): This setting directs most of the air to the windshield and side window vents. Mode Buttons (Outside Air): Press this button to send outside air into your vehicle. The light in the button will glow when outside air is in use. Using this setting while trying to defrost or defog the windows will help clear the vents of moisture. While floor, defog or defrost mode is selected, the system will automatically go to outside air mode. (Recirculation): Press this button to limit the amount of outside air entering your vehicle. The light in the button will glow when recirculation is in use. You may use this setting to limit odors entering your vehicle. Operating the Heating/Ventilation/Air Conditioning (HVAC) system in the recirculation mode may cause fogging of the vehicle's windows when the weather is cold and damp. To clear the fog, switch the HVAC system to either the defog or defrost mode and increase the fan speed. To avoid re-fogging of the windows, operate the HVAC system in the outside air mode. A/C (Air Conditioning): Press this button to turn the air conditioning compressor on and off. The light in the button will glow when the air conditioning is in use. 3-5