GMC 2008 Acadia - Manual (Page 177)

To clear fog from the rear seat side windows, select the
bi-level mode on the rear climate control system and
direct the headliner outlets toward the side windows.
0
(Defrost): Press this button to remove fog or
frost from the windshield more quickly. This mode
directs most of the air to the windshield and side window
vents and some to the floor vents. In this mode, the
system automatically forces outside air into the vehicle.
The recirculation mode cannot be selected while in
the defrost mode. The air conditioning compressor
runs automatically in this setting, unless the outside
temperature is close to freezing. Do not drive the
vehicle until all the windows are clear.
While in defrost mode, if the PASS button is pressed,
the PASS button indicator will flash three times to
let you know that the passenger climate control system
cannot be activated. If the passenger temperature
buttons are adjusted while in defrost mode, the driver
temperature indicator will change. The passenger
temperature will not be displayed.
AUX (Auxiliary): Press this button to turn the
rear heating and air conditioning on. See Rear Air
Conditioning and Heating System on page 3-36 or
Rear Air Conditioning and Heating System and
Electronic Climate Controls on page 3-38.
Rear Window Defogger
The rear window defogger uses a warming grid to
remove fog from the rear window.
<
(Rear Window Defogger): Press this button to
turn the rear window defogger on or off. The rear
window defogger stays on for about 10 minutes after
the button is pressed, before turning off. The defogger
can also be turned off by pressing the button again
or by turning off the engine. Do not drive the vehicle
until all the windows are clear.
If your vehicle has heated outside rearview mirrors,
the mirrors will heat to help clear fog or frost from the
surface of the mirror when the rear window defog
button is pressed.
Notice: Do not use a razor blade or sharp object
to clear the inside rear window. Do not adhere
anything to the defogger grid lines in the rear glass.
These actions may damage the rear defogger.
Repairs would not be covered by your warranty.
3-35