
Black plate (44,1)GMC Sierra Owner Manual - 2011
5-44 Instruments and Controls
Engine Cooling System
Messages
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 5‑17. 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
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 10‑25 for more information.
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 5‑17.
See Overheated Engine Protection
Operating Mode on page 10‑28 for
information on driving to a safe
place in an emergency.
ENGINE OVERHEATED STOP
ENGINE
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 10‑25 for more information.
This message displays and a
chime may sound if the engine
cooling system reaches unsafe
temperatures for operation. Stop
and turn off the vehicle as soon as
it is safe to do so to avoid severe
damage. This message clears when
the engine has cooled to a safe
operating temperature.

Black plate (1,1)GMC Sierra Owner Manual - 2011
Climate Controls 8-1
Climate Controls
Climate Control Systems
Climate Control Systems(with Air Conditioning) . . . . . . . 8-1
Climate Control Systems (with Heater Only) . . . . . . . . . . . 8-4
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . . . . . . . 8-5
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . 8-11
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

Black plate (2,1)GMC Sierra Owner Manual - 2011
8-2 Climate Controls
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.
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.

Black plate (3,1)GMC Sierra Owner Manual - 2011
Climate Controls 8-3
?(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.#(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.
<(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 - 2011
Climate Controls 8-5
6(Floor):Air is directed to the
floor outlets, with some air directed
to the windshield, side window, 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.
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 (7,1)GMC Sierra Owner Manual - 2011
Climate Controls 8-7
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
help quickly cool down the air
inside the vehicle. The light
on the button comes on in
recirculation.
2. Set the driver and passenger temperature.
To find your comfort setting, start
with a 23°C (74°F) temperature
setting and allow about
20 minutes for the system to
regulate. Use the driver or
passenger temperature buttons
to adjust the temperature setting
as necessary. If a temperature
setting of 15°C (60°F) is chosen,
the system remains at the
maximum cooling setting.
If a temperature setting of
32°C (90°F) is chosen, the system remains at the maximum
heat setting. Choosing either
maximum setting will not cause
the vehicle to heat or cool any
faster.
Do not cover the solar sensor
located on the top of the instrument
panel near the windshield.
This sensor regulates air
temperature based on sun load.
For more information on the solar
sensor, see “Sensors”later in this
section.
To avoid blowing cold air in cold
weather, the system delays
turning the fan on until warm air
is available. The length of delay
depends on the engine coolant
temperature. Pressing the fan
switch overrides this delay and
changes the fan to a selected
speed.

Black plate (8,1)GMC Sierra Owner Manual - 2011
8-8 Climate Controls
Manual Operation
D C(Fan Control):Press these
buttons to increase or decrease the
fan speed.
Pressing either fan button while in
automatic control places the fan
under manual control. The fan
setting remains displayed and
the AUTO light turns off. The air
delivery mode remains under
automatic control.
H G(Air Delivery Mode Control):
Press these buttons to change the
direction of the airflow in the vehicle.
Repeatedly press either button until
the desired mode appears on the
display.
Pressing either mode button while
the system is off changes the air
delivery mode without turning the
system on. Pressing either mode button while in
automatic control places the mode
under manual control. The air
delivery mode setting displays and
the AUTO light turns off. The fan
remains under automatic control.
H(Vent):
Air is directed to the
instrument panel outlets.
)(Bi-Level): Air is divided
between the instrument panel and
floor outlets. Some air is directed
toward the windshield and side
window outlets.
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.

Black plate (9,1)GMC Sierra Owner Manual - 2011
Climate Controls 8-9
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.
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 those modes,
the indicator light flashes three
times and then 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.