Hummer 2005 H2 - Manual (Page 164)

Defogging and Defrosting
You can use either defog or front defrost to clear fog or
frost from your windshield. Use the defog mode to
clear the windows of fog or moisture. Use the front
defrost button to defrost the front windshield.
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(Defog): Use this setting to clear the windows of fog
or moisture. Press the mode button to select this
setting. This setting will deliver air to the floor and
windshield outlets.
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(Front Defrost): Press the front defrost button to
defrost the windshield. The system will automatically
control the fan speed if you select defrost from AUTO
mode. If the outside temperature is 40°F (4°C) or
warmer, your air conditioning compressor will
automatically run to help dehumidify the air and dry the
windshield.
Rear Window Defogger
If your vehicle has this feature, the lines you see on the
rear window warm the glass. The rear window
defogger uses a warming grid to remove fog from the
rear window.
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(Rear): Press this button to turn the rear window
defogger on or off. An indicator light in the button
will come on to let you know that the rear window
defogger is activated.
The rear window defogger will turn off about 10 minutes
after the button is pressed. If you need additional
warming time, press the button again.
If your vehicle is equipped with heated mirrors this
button will activate them.
Notice: Using a razor blade or sharp object to clear
the inside rear window may damage the rear
window defogger. Repairs would not be covered by
your warranty. Do not clear the inside of the rear
window with sharp objects.
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