2009 Buick LaCrosse Owner's Manual - Page 146

h (Recirculate): Press to turn the recirculation mode on. An indicator light comes on to show that recirculation is on. This mode recirculates and helps to quickly heat or cool the air inside the vehicle. It can be used to prevent the outside air and odors from entering the vehicle. Operation in this mode during periods of high humidity and cool outside temperatures may result in increased window fogging. If window fogging is experienced, select the defrost mode. To prevent the air inside the vehicle from becoming stale, after five minutes recirculation lets some outside air into the vehicle. Rear Window Defogger The rear window defogger uses a warming grid to remove fog from the rear window. 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 turned on again, the defogger only runs for about 20 minutes before turning off. The defogger can also be turned off by turning off the engine. The heated outside rearview mirrors, help to clear fog or frost from the surface of the mirror when the rear window defog button is pressed. Do not drive the vehicle until all windows are clear. Notice: Do not use anything sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs would not be covered by the vehicle warranty. Do not attach a temporary vehicle license, tape, a decal or anything similar to the defogger grid. < (Rear): Press turn the rear window defogger on or off. An indicator light comes on to show that the rear window defogger is on. 3-24