2007 Buick LaCrosse Owner's Manual - Page 176

Defogging and Defrosting Fog on the inside of windows is a result of high humidity (moisture) condensing on the cool window glass. This can be minimized if the climate control system is used properly. There are two modes to clear fog or frost from your windshield. Use the floor/defog mode to clear the windows of fog or moisture and warm the passengers. Use defrost to remove fog or frost from the windshield more quickly. 1 (Defrost): Press this button to direct most of the air to the windshield, with some air directed to the side windows. In this mode, the system will automatically turn off the recirculation and run the air conditioning compressor, unless the outside temperature is near or below freezing. Pressing the recirculation button will have no effect other than turning on the indicator light while in defrost mode. Do not drive the vehicle until all windows are clear. - (Floor/Defog): Press this button to direct the air between the windshield, floor outlets and side windows. When you select this mode, the system turns recirculation off and runs the air conditioning compressor unless the outside temperature is near or below freezing. Pressing the recirculation button will have no effect other than turning on the indicator light while in floor/defog mode. Sensors The solar sensor on the vehicle monitors the solar heat and the air inside of the vehicle. This information is used 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. 176