GMC 2003 Savana Van Owner's Manual page 143

Defogging and Defrosting
Fog on the inside of windows is a result of high humidity
(moisture) condensing on the cool window glass. This
can be minimized if the climate control system is
used properly.
Turn the knob on the right of the climate control panel
to select the defog or defrost mode.
+3
(Blend): With this setting, the outside air comes out
of both the floor and defroster outlets. Adjust the
temperature knob for warmer or cooler air. The air
conditioning compressor may operate in this setting to
dehumidify the air.
9
(Defrost): This setting operates the defroster. Most
of the air comes out near the windshield, with some
going to the floor outlets and front side windows. The air
conditioning compressor may operate in this setting to
dehumidify the air.
The blend setting is useful for cold weather with a large
number of passengers or very humid conditions to
help keep the windshield clear. Use defrost to remove
fog or ice from the windshield quickly in extremely
cold conditions. The temperature knob should be in the
red area and the fan control toward high.
Do not drive the vehicle until all the windows are clean.
Rear Window Defogger
Press this button to turn the rear window defogger on or
off. Be sure to clear as much snow from the window
as possible.
The rear window defogger uses a warming grid to
remove fog or frost from the rear window and will only
work when the ignition is RUN.
The rear window defogger will turn off several minutes
after the button is pressed. If turned on again, the
defogger will run for several more minutes before turning
off. The defogger can also be turned off by pressing
the button again or by turning off the engine.
Notices 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 defogger and the
repairs would not be covered by your warranty.
Do not attach a temporary vehicle license, tape, a
decal or anything similar to the defogger grid.
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