2010 Buick Lucerne Owner's Manual - Page 187

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 3‑36 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. Outlet Adjustment Use the levers, located in the middle of the front outlets, to change the direction of the airflow. Use the thumbwheel located between the outlets to turn them on and off. If the vehicle has rear seat outlets, adjust the direction of the airflow using the lever in the center of each outlet. Operation Tips . Clear away any ice, snow, or leaves from the air inlets at the base of the windshield that could block the flow of air into the vehicle. Use of non-GM approved hood deflectors can adversely affect the performance of the system. Keep the path under the front seats clear of objects to help circulate the air inside the vehicle better. . . 4-27