Ventilation System - Chevrolet 1999 Lumina Owner's Manual

It will turn itself off after about 10 minutes. If you turn it
on again, the defogger will only run for about five
minutes before turning off. You can also turn it off by
turning off the ignition or pressing the button again.
Do not attach anything like a temporary vehicle license
or decal across the defogger grid.
NOTICE:
Don't use a razor blade or something 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.
Don't put decals there because you might have to
scrape them off.

Ventilation System

Adjust the direction of airflow by moving the 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
For mild outside temperatures when little heating or
cooling is needed, use VENT to direct outside air
through your vehicle.
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.
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