2003 Pontiac Bonneville Owner's Manual - Page 145

If you are in city traffic, and your vehicle is stopped and idling, or the weather is hot, the system may switch from the outside air mode to the recirculation mode. To prevent the air inside of your vehicle from becoming too stale, be sure to return to the outside air mode periodically. RECIRC (Recirculation): Press this button to limit the amount of outside air coming into the vehicle. It can be used to prevent outside air and odors from entering your vehicle or to help heat or cool the air inside your vehicle more quickly. Press this button to turn the recirculation mode on or off. When the button is pressed, an indicator light will come on. The recirculation mode cannot be used with the FRONT defrost mode. A/C (Air Conditioning}: Press this button to override the automatic system and turn the air conditioning system on or off. When A/C is pressed, an indicator light in the button will come on to let you know that it is activated. When in AUTO, the air conditioning compressor will come on automatically, as necessary. The air conditioning compressor will also run when you select the FRONT defrost mode and outside temperatures are above freezing. On hot days, open the windows to let hot inside air escape; then close them. This helps to reduce the time it takes for your vehicle to cool down. It also helps the system to operate more efficiently. For quick cool down on hot days, press the AUTO button and the system will automatically enter recirculation mode and the temperature will be at the full cold position for maximum cooling. Using these settings together for long periods of time may cause the air inside of your vehicle to become too dry. To prevent this from happening, after the air in your vehicle has cooled, turn the recirculation mode off. The air conditioning system removes moisture from the air, so you may sometimes notice a small amount of water dripping underneath your vehicle while idling or after turning off the engine. This is normal. & Sensors The solar sensor on your vehicle monitors the solar radiation and the air inside of your vehicle, then uses the information to maintain the selected temperature by initiating needed adjustments to the temperature, the fan speed and the air delivery system. The system may also supply cooler air to the side of the vehicle facing the sun. The recirculation mode will also be activated, as necessary. Do not cover the solar sensor located in the center of the instrument panel, near the windshield, or the system will not work properly. a 3-30