2008 GMC ACADIA air condition compressor

Airow Mode Control:Turn the right knob clockwise
or counterclockwise to direct the airow 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 oor
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 oor outlets.
6(Floor):This mode directs most of the air to
the oor outlets, with some of the air directed to the
windshield, side window outlets, and second row
oor outlets. In this mode, the system automatically
selects outside air. Recirculation cannot be selected
when in Floor Mode.
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 oor, defrost,
or defogging modes. If you try to select recirculation in
one of those modes, the indicator ashes three times
and turns off. The air conditioning compressor also
comes on when this mode is activated unless the
outside air temperature is less than 40°F (4°C). While
in recirculation mode the windows may fog when the
weather is cold and damp. To clear the fog, select either
the defog or defrost mode and increase the fan speed.
#(Air Conditioning):Press this button on the left
knob to turn the air conditioning system on or off.
When A/C is pressed, an indicator light comes on to
show that the air conditioning has been activated. The air
conditioning compressor does not operate when outside
temperatures fall below 40°F (4°C). The indicator light
ashes three times and turns off when outside conditions
affect air conditioning operation. This is normal.
3-27

For quicker cool down on hot days, do the following:
1. Open the windows to let hot air escape.
2. Select the vent mode.
3. Select the air conditioner.
4. Select the coolest temperature.
5. Select the highest fan speed.
6. Close the windows after the hot air has escaped.
7. Once the vehicle’s interior temperature is below
the outside temperature, select recirculation
mode for better cooling.
This helps to reduce the time it takes for the vehicle
to cool down. It also helps the system to operate
more efficiently.
Using recirculation for long periods of time may
cause the air inside of the vehicle to become too dry.
To prevent this from happening, after the inside of
the vehicle has cooled, turn the recirculation mode off.
The air conditioning system removes moisture from
the air, so you might notice a small amount of water
dripping underneath the front center and right rear
of the vehicle while idling or after turning off the engine.
This is normal.Defogging and Defrosting
Fog on the inside of the 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. There are two modes to clear
fog or frost from the windshield. Turn the right knob
clockwise to select the defog or defrost mode.
-(Defog):The defog mode is used to clear the
windows of fog or moisture and warm the passengers.
This mode directs air to the windshield, oor outlets,
and side window vents. When you select this mode,
the system turns off recirculation and runs the air
conditioning compressor unless the outside temperature
is less than 40°F (4°C). The recirculation mode
cannot be selected while in the defog mode. Do not
drive the vehicle until all the windows are clear.
0(Defrost):The defrost mode is used 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 oor vents. In this mode, the
system will automatically force outside air into your
vehicle. The recirculation mode cannot be selected while
in the defrost mode. The air conditioning compressor
will run automatically in this setting, unless the outside
temperature is less than 40°F (4°C). Do not drive
the vehicle until all the windows are clear.
3-28

Driver’s Side Temperature Control
The driver side temperature buttons are used to adjust
the temperature of the air coming through the system on
the driver side. The temperature can be adjusted even
if the system is turned off. This is possible since outside
air will always ow through the system as the vehicle is
moving forward unless it is set to recirculation mode.
See “Recirculation” later in this section.
Press the + or−buttons to increase or decrease the
temperature. The driver side temperature display will
show the temperature setting decreasing or increasing.
Passenger’s Side Temperature Control
The passenger’s temperature buttons can be used to
change the temperature of the air coming through
the system on the passenger side of the vehicle.
The temperature can be adjusted even if the system
is turned off. This is possible since outside air will
always ow through the system as the vehicle is
moving forward unless it is set to recirculation mode.
See “Recirculation” later in this section.
Press the + or−buttons to increase or decrease the
temperature. The passenger side display will show
the temperature setting decreasing or increasing.
The passenger’s temperature setting can be set to
match the driver’s temperature setting by pressing the
PASS button and turning off the PASS indicator.When the passenger’s temperature setting is set
different than the driver’s setting, the indicator on the
PASS button comes on and both the driver side
and passenger side temperature displays are shown.
Automatic Operation
AUTO (Automatic):When automatic operation is
active the system controls the inside temperature,
the air delivery, and the fan speed.
Use the steps below to place the entire system in
automatic mode:
1. Press the AUTO button.
When AUTO is selected, the display shows the
current temperature(s) selected and AUTO is on
the display. The current delivery mode and fan
speed also display for approximately 5 seconds.
When AUTO is selected, the air conditioning
operation and air inlet are automatically controlled.
The air conditioning compressor runs when the
outside temperature is over about 40°F (4°C).
The air inlet is normally set to outside air. If it is
hot outside, the air inlet can automatically switch
to recirculate inside air to help quickly cool
down your vehicle. The light comes on the
recirculation button while in recirculation.
3-30

The air delivery mode setting remains displayed,
the word AUTO is no longer displayed, and the
AUTO button indicator light turns off.
H(Vent):This setting delivers air to the instrument
panel outlets.
)(Bi-Level):This mode directs air to the instrument
panel outlets and to the oor 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 oor outlets.
6(Floor):This mode directs most of the air to
the oor outlets, with some of the air directed to the
windshield, side window outlets, and second row
oor outlets. In this mode, the system automatically
selects outside air. Recirculation cannot be selected
in oor mode.
-(Defog):See “Defogging and Defrosting” later
in this section.
@(Recirculation):Press this button to turn the
recirculation mode on. When the button is pressed,
an indicator light comes on.
This mode keeps outside air from entering the vehicle.
It can be used to reduce outside air and prevent
odors from entering your vehicle. Recirculation also
helps to quickly cool the warmer air inside your vehicle.
The recirculation mode cannot be used with oor, defrost,
or defogging modes. If you try to select recirculation in
one of those modes, the indicator ashes three times and
turns off. The air conditioning compressor also comes on
when this mode is activated. While in recirculation mode
the windows may fog when the weather is cold and damp.
To clear the fog, select either the defog or defrost mode
and increase the fan speed.
Press the button again to turn off the recirculation mode.
It automatically turns off when the engine is turned off and
must be re-selected when the engine is turned on again.
3-32

Air Conditioning
#
(Air Conditioning):Press this button to turn the
air conditioning (A/C) compressor on and off. When air
conditioning is selected, an indicator light comes on
to show that the air conditioning has been activated.
The air conditioning compressor does not work
when outside temperatures fall below 40°F (4°C).
Pressing this button when the outside temperature
is too cool makes the air conditioning indicator
ash three times and turn off to let you know the
air conditioning mode is not available. If the air
conditioning is on and the outside temperature
drops below a temperature which is too cool for
air conditioning to be effective, the air conditioning
light turns off to show that the air conditioning mode
has been canceled.
On hot days, open the windows long enough to let
hot inside air escape. This helps to reduce the time
it takes for the vehicle to cool down. It also helps
the system to operate more efficiently.
The air conditioning system removes moisture from the
air, so a small amount of water may drip underneath
your vehicle while idling or after turning off the engine.
This is normal.
Sensors
The solar sensor, located in the defrost grille in the
middle of the instrument panel, monitors the solar
radiation. Do not cover the solar sensor or the system
will not work properly.
3-33

The interior temperature sensor located on the
instrument panel to the right of the steering column,
measures the temperature of the air inside the vehicle.
There is also an exterior temperature sensor located
behind the front grille. This sensor reads the outside air
temperature and helps maintain the temperature inside
the vehicle. Any cover on the front of the vehicle could
cause a false reading in the displayed temperature.The climate control system uses the information from
these sensors to maintain your comfort setting by
adjusting the outlet temperature, fan speed, and the
air delivery mode. The system may also supply cooler
air to the side of the vehicle facing the sun. The
recirculation mode will also be used as needed to
maintain cool outlet temperatures.
Defogging and Defrosting
Fog on the inside of the 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. There are two modes to
clear fog or frost from your windshield.
Use the mode up and down arrows to select the defog
mode. Use the defrost button to select the defrost mode.
-(Defog):The defog mode is used to clear the
windows of fog or moisture and warm the passengers.
This mode directs air to the windshield, oor outlets,
and side window vents. When this mode is selected,
the system turns off recirculation and runs the air
conditioning compressor unless the outside temperature
is close to freezing. The recirculation mode cannot be
selected while in the defog mode. Do not drive the
vehicle until all the windows are clear.
3-34

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 oor 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 ash 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. SeeRear Air
Conditioning and Heating System on page 3-36or
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

DRIVER DOOR OPEN
This message displays and a chime sounds if the
driver door is not fully closed and the vehicle is in
a drive gear. Stop and turn off the vehicle, check
the door for obstructions, and close the door again.
Check to see if the message still appears on the DIC.
ENGINE HOT A/C
(Air Conditioning) OFF
This message displays when the engine coolant
becomes hotter than the normal operating temperature.
SeeEngine Coolant Temperature Gage on page 3-49.
To avoid added strain on a hot engine, the air
conditioning compressor automatically turns off.
When the coolant temperature returns to normal,
the air conditioning compressor turns back on.
You can continue to drive your vehicle.
If this message continues to appear, have the
system repaired by your dealer/retailer as soon
as possible to avoid damage to the engine.
ENGINE OVERHEATED IDLE ENGINE
Notice:If you drive your vehicle while the engine
is overheating, severe engine damage may occur.
If an overheat warning appears on the instrument
panel cluster and/or DIC, stop the vehicle as soon
as possible. Do not increase the engine speed above
normal idling speed. SeeEngine Overheating on
page 5-25for more information.
This message displays when the engine coolant
temperature is too hot. Stop and allow the vehicle
to idle until it cools down. SeeEngine Coolant
Temperature Gage on page 3-49.
SeeOverheated Engine Protection Operating Mode
on page 5-26for information on driving to a safe place
in an emergency.
3-68