2012 GMC SIERRA 1500 air conditioning

Black plate (17,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Keys, Doors, and Windows 2-17
Manual Folding
If equipped with manual folding
mirrors, push the mirror toward the
vehicle. Push the mirror outward, to
return to its original position.
Manually fold the mirrors inward to
prevent damage when going
through an automatic car wash.
Automatic Dimming
If equipped with an automatic
dimming mirror, the driver outside
mirror automatically dimes for the
glare of the headlamps from behind.
This feature is controlled by the on
and off setting on the inside
rearview mirror.
SeeAutomatic Dimming Rearview
Mirror on page 2‑18.
Turn Signal Indicator
The vehicle may also have a turn
signal indicator on the mirror. An
arrow on the mirror flashes in the
direction of the turn or lane change.
Heated Mirrors
For vehicles with heated mirrors:
1(Rear Window Defogger):
Press to heat the mirrors. If the
vehicle has a towing mirror, only the
upper glass of the mirror is heated.
The lower convex part of the towing
mirror is not heated.
Depending on the vehicle's features,
see “Rear Window Defogger” under
Climate Control Systems (with Air
Conditioning) on page 8‑1 or
Climate Control Systems (with
Heater Only) on page 8‑4 orDual
Automatic Climate Control System
on page 8‑5 for more information.
Park Tilt Mirrors
If the vehicle has the memory
package, the passenger and/or
driver mirror tilts to a preselected
position when the vehicle is in
R (Reverse). This feature lets the
driver view the curb when parallel
parking. The mirror(s) return to the
original position when the vehicle is
shifted out of R (Reverse), or the
ignition is turned off or to
OFF/LOCK.
Turn this feature on or off through
the Driver Information Center (DIC).
SeeVehicle Personalization (With
DIC Buttons) on page 5‑48 for more
information.

Black plate (41,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-41
HOOD OPEN
This message displays and a chime
may sound if the hood is not fully
closed. Stop and turn off the
vehicle, check the hood for
obstructions, and close the hood
again. Check to see if the message
still appears on the DIC.
LEFT REAR DOOR OPEN
(Crew Cab)
This message displays and a chime
may sound if the driver side rear
door is not fully closed and the
vehicle is shifted out of P (Park).
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.
PASSENGER DOOR OPEN
This message displays and a chime
may sound if the front passenger
door is not fully closed and the
vehicle is shifted out of P (Park).
Stop and turn off the vehicle, checkthe door for obstructions, and close
the door again. Check to see if the
message still appears on the DIC.
RIGHT REAR DOOR OPEN
(Crew Cab)
This message displays and a chime
may sound if the passenger side
rear door is not fully closed and the
vehicle is shifted out of P (Park).
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 Cooling System
Messages
Notice:
If you drive the 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.
See Engine Overheating on
page 10‑22 for more information.
ENGINE HOT A/C (Air
Conditioning) TURNED OFF
This message displays when the
engine coolant becomes hotter than
the normal operating temperature.
SeeEngine Coolant Temperature
Gauge on page 5‑16. 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 as soon as possible to avoid
damage to the engine.
ENGINE OVERHEATED IDLE
ENGINE
This message displays when the
engine coolant temperature is too
hot. Stop and allow the vehicle to
idle until it cools down. See Engine
Coolant Temperature Gauge on
page 5‑16.

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Climate Controls 8-1
Climate Controls
Climate Control Systems
Climate Control Systems (withAir Conditioning) . . . . . . . . . . . . . 8-1
Climate Control Systems (with Heater Only) . . . . . . . . . . . . . . . . . 8-4
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . . . . . . . 8-5
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . 8-10
Climate Control Systems
Climate Control Systems (with Air Conditioning)
With this system the heating, cooling, and ventilation can be controlled.
A. Fan Control
B. Temperature Control
C. Air Delivery Mode Control
D. Air Conditioning
E. Outside Air
F. Recirculation
G. Rear Window Defogger Temperature Control:
Turn
clockwise or counterclockwise
to increase or decrease the
temperature inside the vehicle.
9(Fan Control): Turn clockwise
or counterclockwise to increase or
decrease the fan speed. Turn the
knob all the way counterclockwise
to turn the front system off.

Black plate (2,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
8-2 Climate Controls
Air Delivery Mode Control:Turn
clockwise or counterclockwise to
change the direction of the airflow
inside the vehicle. The knob can be
positioned between two modes to
select a combination of those
modes.
Select from the following:
H(Vent): Air is directed to the
instrument panel outlets.
)(Bi-Level): Air is divided
between the instrument panel and
floor outlets.
6(Floor): Air is directed to the
floor outlets, with some air directed
to the windshield and side window
outlets. In this mode, the system
automatically selects outside air.
Recirculation cannot be selected in
floor mode.
-(Defog): This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents.
0(Defrost): This mode removes
fog or frost from the windshield
more quickly. Air is directed to the
windshield and the side window
vents, with some air directed
to the floor vents. The system
automatically forces outside air into
the vehicle.
The recirculation mode cannot be
selected in the defog or defrost
mode. When either mode is
selected, the system runs the air
conditioning compressor, unless
the outside temperature is close to
freezing.
Do not drive the vehicle until all the
windows are clear.
:(Outside Air): Press to turn
the outside air mode on. An
indicator light comes on to show
that outside air is on. In this mode
outside air circulates throughout
the vehicle. The outside air mode
can be used with all modes,
but it cannot be used with the
recirculation mode.
?(Recirculation): Press to turn
the recirculation mode on. An
indicator light comes on to show
that recirculation is on.
This mode recirculates and helps
to quickly cool the air inside the
vehicle. It can be used to help
prevent outside air and odors from
entering the vehicle.
The recirculation mode cannot be
used with floor, defog or defrost
modes. If recirculation is selected
with one of these modes, the
indicator light flashes three times
and then turns off. 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.
The recirculation mode can be
turned off by pressing the outside
air button, or by turning off the
ignition.

Black plate (3,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Climate Controls 8-3
#(Air Conditioning):Press to
turn the air conditioning system on
or off. An indicator light comes on to
show that the air conditioning is on.
The air conditioning can be selected
in any mode as long as the fan
switch is on.
The air conditioning system
removes moisture from the air, so a
small amount of water might drip
under the vehicle while idling or
after turning off the engine. This is
normal.Rear Window Defogger
For vehicles with a rear window
defogger, a warming grid is used to
remove fog from the rear window.
1(Rear): Press to turn the rear
window defogger on or off. An
indicator light on the button comes
on to show that the rear window
defogger is on.
The rear window defogger only
works when the ignition is in ON/
RUN. The rear window defogger
stays on for approximately
10 minutes after the button is
pressed, unless the ignition is
turned to ACC/ACCESSORY or
LOCK/OFF. The defogger can also
be turned off by turning off the
engine. Notice:
Do not use anything
sharp on the inside of the rear
window. If you do, you could cut
or damage the warming grid, and
the repairs would not be covered
by the vehicle warranty. Do not
attach a temporary vehicle
license, tape, a decal, or anything
similar to the defogger grid.

Black plate (5,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Climate Controls 8-5
0(Defrost):This mode removes
fog or frost from the windshield
more quickly. Air is directed to the
windshield and the side window
vents, with some air directed
to the floor vents. The system
automatically forces outside air into
the vehicle.
Do not drive the vehicle until all the
windows are clear.Dual Automatic Climate Control System
The heating, cooling, and ventilation in the vehicle can be controlled with
this system. The vehicle also has a flow-through ventilation system
described later in this section.
A. Driver and Passenger Temperature Controls
B. Fan Control
C. AUTO
D. Defrost
E. Recirculation
F. Outside Air G. Air Delivery Mode Control
H. Display
I. On/Off
J. Rear Window Defogger
K. Air Conditioning
L. PASS (Passenger)

Black plate (6,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
8-6 Climate Controls
O(On/Off):Press to turn the
climate control system on or off.
Outside air still enters the vehicle,
and is directed to the floor. This
direction can be changed by
pressing the mode button.
Recirculation can be selected once
you have selected vent or bi-level
mode. The temperature can also be
adjusted using either temperature
button. If the air delivery mode or
temperature settings are adjusted
with the system off, the display
illuminates briefly to show the
settings and then returns to off. The
system can be turned back on by
pressing either
O,D,C,#, the
defrost or the AUTO button.
Driver and Passenger Side
Temperature Controls
The driver and passenger side
temperature buttons are used to
adjust the temperature of the air
coming through the system on the
driver or passenger side of the
vehicle. The temperature can be
adjusted even if the system is turned off. This is possible since
outside air always flows 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 cabin temperature.
The driver side or passenger side
temperature display shows the
temperature setting increasing or
decreasing.
The passenger temperature setting
can be set to match the driver
temperature setting by pressing
the PASS button and turning
off the PASS indicator. When the
passenger temperature setting is
set different than the driver setting,
the indicator on the PASS button
illuminates and both the driver side
and passenger side temperature
displays are shown.
When in defrost mode the
passenger temperature setting
cannot be changed.
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 changes to show the
current temperature(s) and
AUTO is lit on the display. The
current air delivery mode and
fan speed are also displayed for
about five seconds.
When AUTO is selected, the air
conditioning operation and air
inlet are automatically controlled.
The air conditioning compressor
may run when the outside
temperature is above freezing.
The air inlet will normally be set
to outside air. If it is hot outside,
the air inlet may automatically
switch to the recirculate mode to

Black plate (8,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
8-8 Climate Controls
6(Floor):Air is directed to the
floor outlets, with some to the
windshield, side window outlets, and
second row floor outlets. In this
mode, the system automatically
selects outside air.
-(Defog): This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents. In
this mode, 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
defrost mode.
0(Defrost): This mode removes
fog or frost from the windshield
more quickly. Air is directed to the
windshield and side window vents,
with some directed to the floor
vents. In this mode, the system
automatically forces outside air
into the vehicle and runs the air
conditioning compressor unless the
outside temperature is close to freezing. The recirculation mode
cannot be selected while in the
defrost mode.
The passenger temperature control
cannot be activated while in defrost
mode. If the PASS button is
pressed, the button indicator flashes
three times and will not work. If the
passenger temperature buttons are
adjusted, the driver temperature
indicator changes. The passenger
temperature will not be displayed.
If vent, bi-level, or floor mode is
selected again, the climate control
system displays the previous
temperature settings.
Do not drive the vehicle until all
windows are clear.
#(Air Conditioning):
Press to
turn the air conditioning (A/C)
compressor on and off. An indicator
light comes on to show that the air
conditioning is on.
If this button is pressed when the
air conditioning compressor is
unavailable due to outside conditions, the indicator flashes
three times and then turns off.
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 might drip
under the vehicle while idling or
after turning off the engine. This is
normal.
@(Recirculation):
Press to
turn the recirculation mode on. An
indicator light comes on to show
that recirculation is on.