1999 Pontiac Grand Prix Owner's Manual - Page 161

yellowblue The rear window defogger uses a warming grid to remove fog from the rear window. Press the button to turn the rear defogger on. It will turn itself off after about ten minutes. If you turn it on again, the rear defogger will only run for about five minutes before turning off. You can also turn it off by pressing the button again. Do not attach anything like a temporary vehicle license or decal across the defogger grid. Ventilation System NOTICE: Don't use a razor blade or anything else sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs wouldn't be covered by your warranty. Adjust the direction of airflow by moving the louvered vents. Your vehicle's flow-through ventilation system supplies outside air into the vehicle when it is moving. Outside air will also enter the vehicle when the air conditioning fan is running. Ventilation Tips D Keep the hood and front air inlet free of ice, snow or any other obstruction, such as leaves. The heater and defroster will work far better, reducing the chance of fogging the inside of your windows. 3-9