Pontiac 1993 Grand Am Owner's Manual page 107

Comfort Controls & Audio Systems
I
Rear Window Defogger
(CONT.:)
I
Flow-Through Ventilation System
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
Your Pontiac's flow-through ventilation
system supplies outside air into the
vehicle when it is moving. Outside air
will also enter the vehicle when the
heater or the air conditioning fan is
running.
Ventilation Tips
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.
When you enter a vehicle in cold
weather, turn the fan control knob to
HIGH for a few moments before
driving off. This helps clear the intake
ducts of snow and moisture, and
reduces the chance of fogging the
inside of your windows.
clear of objects. This helps air to
circulate throughout your vehicle.
Keep the air path under the front seats