GMC 2007 Acadia Owner's Manual page 200

Temperature Control: Turn the center knob
clockwise or counterclockwise to increase
or decrease the temperature of the air flowing
from the system.
Airflow Mode Control: Turn the right knob
clockwise or counterclockwise to direct the airflow
inside of the vehicle.
To change the current mode, select one of the
following:
H
(Vent): This mode directs air to the instrument
panel outlets.
)
(Bi-Level): This mode directs about half of
the air to the instrument panel outlets and
half to the floor outlets. A little air is directed
towards the windshield and side window outlets.
Cooler air is directed to the upper outlets and
warmer air to the floor outlets.
6
(Floor): This mode directs most of the air to
the floor outlets, with some of the air directed
to the windshield, side window outlets, and
second row floor outlets. In this mode, the system
automatically selects outside air. Recirculation
cannot be selected when in Floor Mode.
200
The right knob can also be used to select defog
or defrost mode. For more information, see
"Defogging and Defrosting" later in this section.
By positioning the right knob between two modes,
a combination of those two modes is selected.
@
(Recirculation): Press this button to turn the
recirculation mode on or off. The indicator light
on the button turns on when this mode is selected.
This mode keeps outside air from entering the
vehicle. It can be used to reduce the outside air
and odors entering the vehicle. Recirculation
may also help cool the air inside the vehicle more
quickly once the temperature inside the vehicle
is less than the outside temperature.
The recirculation mode can be turned off in vent
and bi-level modes by pressing the button
again. Recirculation mode automatically turns off
when the engine is turned off and must be
re-selected when the engine is turned on again.
The recirculation mode cannot be used with
floor, defrost, or defogging modes. If you try to
select recirculation in one of those modes,
the indicator flashes three times and turns off.