2007 Buick Lucerne Owner's Manual - Page 190

There is also an exterior temperature sensor located behind the front grille. This sensor reads the outside air temperature and helps maintain the temperature inside the vehicle. Any cover on the front of the vehicle could cause a false reading in the displayed temperature. In order to prevent false temperature readings at startup, the displayed temperature will not change until the following occurs: • Vehicle speed is above 10 mph (16 k/mh) for 5 minutes. • Vehicle speed is above 32 mph (51 k/mh) for 2 and a half minutes. The climate control system uses the information from these sensors to maintain your comfort setting by adjusting the outlet temperature, fan speed, and the air delivery mode. The system may also supply cooler air to the side of the vehicle facing the sun. The recirculation mode will also be used as needed to maintain cool outlet temperatures. 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 from your windshield, defog and defrost. W (Floor/Defog): Use this mode to clear the windows of fog or moisture and to warm the passengers. Turning the control to this mode directs about half of the air to the floor outlets and the remaining air is directed to the side window outlets and to the windshield. When you select this mode, the system turns off recirculation and runs the air-conditioning compressor unless the outside temperature is at or below freezing. The recirculation mode cannot be selected while in the floor/defog mode. 190