2011 Buick Lucern Owner's Manual - Page 180

There is also an interior temperature sensor located next to the steering wheel that measures the temperature of the air inside the vehicle. 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 temperature reading to display. In order to prevent false temperature readings at startup, the displayed temperature will not change until the following occurs: . Rear Window Defogger The rear window defogger uses a warming grid to remove fog or frost from the rear window. < (Rear Defogger): Press to turn the rear window defogger on or off. An indicator light below the button comes on to show that the rear window defogger is on. Be sure to clear as much snow from the rear window as possible. The rear window defogger only works when the ignition is in ON/RUN. The rear window defogger stays on for about 20 minutes after the button is pressed if the vehicle is traveling at slower vehicle speeds. At higher vehicle speeds the rear window defogger may stay on continuously. If turned on again, the defogger only runs for about 10 minutes before turning off. The defogger can be turned off by pressing the button again, by turning the ignition to ACC/ACCESSORY or ON/RUN, or by turning off the engine. The heated outside rearview mirrors will heat to help clear fog or frost from the surface of the mirror when the rear window defogger is on. See Outside Heated Mirrors on page 3 ‑ 34 for more information. Notice: Do not use a razor blade or sharp object to clear the inside rear window. Do not adhere anything to the defogger grid lines in the rear glass. These actions may damage the rear defogger. Repairs would not be covered by your warranty. Vehicle speed is above 10 mph (16 km/h) for five minutes. Vehicle speed is above 32 mph (51 km/h) for two 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. 4-24