
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
248 Climate Controls
Climate Control Systems (with Air Conditioning)
With this system the heating, cooling, and ventilation can be controlled.
1. Fan Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Defrost
5. TEMP (Temperature Control)
6.
K(Rear Window Defogger, If
Equipped)
f(Outside Heated Mirror, If
Equipped)
8(Outside Air, If Equipped)
7.
@Air Recirculation
TEMP (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 fan off.
Air Delivery Mode Controls :
Press
Y,\,[, or-to change
the direction of the airflow. An
indicator light comes on in the
selected mode button.
Y(Vent) : Air is directed to the
instrument panel outlets.
\(Bi-Level) : Air is divided
between the instrument panel and
floor outlets.
[(Floor) : Air is directed to the
floor outlets, with some air directed
to the windshield and side window
outlets.
-(Defog) : This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents.
0(Defrost) : Press to clear the
windshield of fog or frost more
quickly. Air is directed to the
windshield and the side window

GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
Climate Controls 249
vents. The system automatically
forces outside air into the vehicle
and the air conditioning compressor
will run, unless the outside
temperature is close to freezing.
Do not drive the vehicle until all the
windows are clear.
SeeAir Vents 0253.
@(Recirculation) : Press to turn
on recirculation. An indicator light
comes on. Air is recirculated to
quickly cool the inside of the
vehicle. It can also be used to help
reduce outside air and odors that
enter the vehicle.
8(Outside Air, If Equipped) :
Press to turn the outside air mode
on. An indicator light on the button
comes on to show that outside is
on. When selected, air from outside
the vehicle circulates throughout the
vehicle. The recirculation mode
cannot be used with the outside
air mode.
f(Outside Heated Mirror, If
Equipped) : Press to turn the
heated mirrors on or off. See
Heated Mirrors 048. A/C (Air Conditioning) :
Press to
turn the air conditioning system on
or off. An indicator light comes on to
show that the air conditioning is
enabled. If the fan is turned off, the
air conditioner will not run. The A/C
light will stay on even if the outside
temperatures are below freezing.
Rear Window Defogger
K(Rear Window Defogger) :
If equipped, 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 defogger turns off if the
ignition is turned to ACC/
ACCESSORY or LOCK/OFF.
If equipped with heated outside
mirrors, they turn on when the rear
window defogger button is on. They
help to clear fog or frost from the
surface of the mirrors.
Caution
Using a razor blade or sharp
object to clear the inside rear
window can damage the rear
window defogger. Repairs would
not be covered by the vehicle
warranty. Do not clear the inside
rear window with sharp objects.

GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
250 Climate Controls
Dual Automatic Climate Control System
With this system the heating, cooling, and ventilation in the vehicle can be
controlled.
For an eAssist vehicle, see the Silverado/Sierra eAssist supplement.
1. Driver Temperature Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger TemperatureControl 7. SYNC (Synchronized
Temperature)
8. Rear Window Defogger
9. Power Button
10. Air Recirculation
11. AUTO (Automatic Operation) Automatic Operation
The system automatically controls
the fan speed, air delivery, air
conditioning, and recirculation in
order to heat or cool the vehicle to
the desired temperature.
When the indicator light is on, the
system is in full automatic operation.
If the air delivery mode or fan
setting is manually adjusted, the
auto indicator turns off and displays
will show the selected settings.
To place the system in
automatic mode:
1. Press AUTO.
2. Set the driver and passenger temperature.
To find your comfort setting,
start with 22 °C (72 °F) and
allow the system time to
stabilize. Then adjust the
temperature as needed for best
comfort.
To improve fuel efficiency and to
cool the vehicle faster, recirculation
may be automatically selected in
warm weather.

GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
Climate Controls 251
The recirculation light will not come
on when automatically controlled.
Press
@to manually select
recirculation; press it again to select
outside air.
Do not cover the solar sensor on the
top of the instrument panel near the
windshield. This sensor regulates
air temperature based on sun load.
See “Sensors” later in this section.
Manual Operation
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 air delivery mode.
9(Fan Control) : Turn clockwise
or counterclockwise to increase or
decrease the fan speed. Press the
knob to turn the fan off.
Press AUTO to return to automatic
operation. Driver and Passenger
Temperature Control :
The
temperature can be adjusted
separately for the driver and
passenger.
Turn the knob clockwise or
counterclockwise to increase or
decrease the driver or passenger
temperature setting.
SYNC (Synchronized
Temperature) : Press to link the
passenger temperature setting to
the driver setting. The SYNC
indicator light will turn on. When the
passenger setting is adjusted, the
SYNC indicator light is off.
The driver side or passenger side
temperature display shows the
temperature setting increasing or
decreasing.
Air Delivery Mode Control :
Press
Y,\,[, or-to change
the direction of the airflow. An
indicator light comes on in the
selected mode button. Changing the mode cancels the
automatic operation and the system
goes into manual mode. Press
AUTO to return to automatic
operation.
Y(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.
[(Floor) : Air is directed to the
floor outlets, with some to the
windshield, side window outlets, and
second row floor outlets.
-(Defog) : This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents. The
system automatically forces outside
air into the vehicle and the air
conditioning compressor will run,
unless the outside temperature is
close to freezing.
0(Defrost) : Press to clear the
windshield of fog or frost more
quickly. Air is directed to the

GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
252 Climate Controls
windshield and the side window
vents. The air conditioning
compressor also comes on, unless
the outside temperature is below
freezing.
Do not drive the vehicle until all
windows are clear.
SeeAir Vents 0253.
A/C (Air Conditioning) : Press to
turn the air conditioning system on
or off. An indicator light comes on to
show that the air conditioning is
enabled. If the fan is turned off, the
air conditioner will not run. The A/C
light will stay on even if the outside
temperatures are below freezing.
@(Recirculation) : Press to turn
on recirculation. An indicator light
comes on. Air is recirculated to
quickly cool the inside of the
vehicle. It can also be used to help
reduce outside air and odors that
enter the vehicle. The air
conditioning compressor also comes
on when this mode is activated.
Rear Window Defogger
The rear window defogger uses a
warming grid to remove fog from the
rear window.
K(Rear Window Defogger) :
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 defogger turns off if the
ignition is turned to ACC/
ACCESSORY or LOCK/OFF.
Caution
Using a razor blade or sharp
object to clear the inside rear
window can damage the rear
window defogger. Repairs would
not be covered by the vehicle
warranty. Do not clear the inside
rear window with sharp objects.
Heated Mirror : If equipped with
heated outside rearview mirrors, the
mirrors heat to help clear fog or frost from the surface of the mirror when
the rear window defog button is
pressed. See
Heated Mirrors 048.
Sensors
The solar sensor, located in the
defrost grille in the middle of the
instrument panel, monitors the solar
heat. Do not cover the solar sensor
or the system will not work properly.
There is also an exterior
temperature sensor 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
including a snow plow, could cause
a false reading in the displayed
temperature.

GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
Driving and Operating 263
{Warning
Driving to the top of a hill at high
speed can cause an accident.
There could be a drop-off,
embankment, cliff, or even
another vehicle. You could be
seriously injured or killed. As you
near the top of a hill, slow down
and stay alert.
. Never go downhill forward or
backward with either the
transmission or transfer case in
N (Neutral). The brakes could
overheat and you could lose
control.
{Warning
If the vehicle has the two‐speed
automatic transfer case, shifting
the transfer case to N (Neutral)
can cause your vehicle to roll
even if the transmission is in
P (Park). This is because the
N (Neutral) position on the
(Continued)
Warning (Continued)
transfer case overrides the
transmission. You or someone
else could be injured. If leaving
the vehicle, set the parking brake
and shift the transmission to
P (Park). Shift the transfer case to
any position but N (Neutral).
. When driving down a hill, keep
the vehicle headed straight
down. Use a low gear because
the engine will work with the
brakes to slow the vehicle and
help keep the vehicle under
control.
{Warning
Heavy braking when going down
a hill can cause your brakes to
overheat and fade. This could
cause loss of control and you or
others could be injured or killed.
Apply the brakes lightly when
(Continued)
Warning (Continued)
descending a hill and use a low
gear to keep vehicle speed under
control.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the
parking brake.
2. Shift into P (Park) and then restart the engine.
.If driving uphill when the
vehicle stalls, shift to
R (Reverse), release the
parking brake, and back
straight down.
. Never try to turn the vehicle
around. If the hill is steep
enough to stall the vehicle,
it is steep enough to cause
it to roll over.
. If you cannot make it up the
hill, back straight down
the hill.

GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
266 Driving and Operating
{Warning
Wet brakes can cause crashes.
They might not work as well in a
quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road is
wet enough and you are going fast
enough. When the vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
. Pass with caution.
. Keep windshield wiping
equipment in good shape.
. Keep the windshield washer fluid
reservoir filled.
. Have good tires with proper
tread depth. See Tires0399.
. Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips include:
.Keep the vehicle serviced and in
good shape.
. Check all fluid levels and brakes,
tires, cooling system, and
transmission.
. Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the
vehicle on a long downhill slope
can cause brake overheating, can
reduce brake performance, and
could result in a loss of braking.
Shift the transmission to a lower
gear to let the engine assist the
brakes on a steep downhill slope.

GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234758) - 2016 - crc - 11/9/15
268 Driving and Operating
{Warning
Snow can trap engine exhaust
under the vehicle. This may
cause exhaust gases to get
inside. Engine exhaust contains
carbon monoxide (CO), which
cannot be seen or smelled. It can
cause unconsciousness and even
death.
If the vehicle is stuck in snow:. Clear snow from the base of
the vehicle, especially any
blocking the exhaust pipe.
. Open a window about 5 cm
(2 in) on the vehicle side
that is away from the wind,
to bring in fresh air.
. Fully open the air outlets on
or under the instrument
panel.
. Adjust the climate control
system to circulate the air
inside the vehicle and set
(Continued)
Warning (Continued)
the fan speed to the highest
setting. See“Climate
Control Systems.”
For more information about CO,
see Engine Exhaust 0285.
To save fuel, run the engine for
short periods to warm the vehicle
and then shut the engine off and
partially close the window. Moving
about to keep warm also helps.
If it takes time for help to arrive,
when running the engine, push the
accelerator pedal slightly so the
engine runs faster than the idle
speed. This keeps the battery
charged to restart the vehicle and to
signal for help with the headlamps.
Do this as little as possible, to
save fuel.
If the Vehicle Is Stuck
Slowly and cautiously spin the
wheels to free the vehicle when
stuck in sand, mud, ice, or snow.
See “Rocking the Vehicle to Get It
Out” later in this section.
The Traction Control System (TCS)
can often help to free a stuck
vehicle. See Traction Control/
Electronic Stability Control 0303.
If TCS cannot free the vehicle, see
“Rocking the Vehicle to Get it Out”
following.
{Warning
If the vehicle's tires spin at high
speed, they can explode, and you
or others could be injured. The
vehicle can overheat, causing an
engine compartment fire or other
damage. Spin the wheels as little
as possible and avoid going
above 56 km/h (35 mph).
For information about using tire
chains on the vehicle, see Tire
Chains 0422.