
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.

Black plate (10,1)GMC Sierra Owner Manual - 2011
8-10 Climate Controls
The recirculation mode can be
turned off by pressing the outside
air button, or by turning off the
ignition.
;(Outside Air):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.
Rear Window Defogger
The rear window defogger uses a
warming grid to remove fog from the
rear window.
<(Rear Window Defogger):
For vehicles with this feature,
press to turn the defogger on or off.
It automatically turns off several
minutes after it has been activated. The defogger can also be turned off
by turning the engine off. Do not
drive the vehicle until all windows
are clear.
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.
Heated Mirror: For vehicles 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 Power Mirrors on
page 2‑16.
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.

Black plate (3,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-3
Death and injury associated with
drinking and driving is a global
tragedy.
Alcohol affects four things that
anyone needs to drive a vehicle:
judgment, muscular coordination,
vision, and attentiveness.
Police records show that
almost 40 percent of all motor
vehicle-related deaths involve
alcohol. In most cases, these
deaths are the result of someone
who was drinking and driving.
In recent years, more than
17,000 annual motor vehicle-related
deaths have been associated with
the use of alcohol, with about
250,000 people injured.
For persons under 21, it is against
the law in every U.S. state to drink
alcohol. There are good medical,
psychological, and developmental
reasons for these laws.
The obvious way to eliminate the
leading highway safety problem is
for people never to drink alcohol
and then drive.Medical research shows that
alcohol in a person's system
can make crash injuries worse,
especially injuries to the brain,
spinal cord, or heart. This means
that when anyone who has been
drinking
—driver or passenger —is
in a crash, that person's chance of
being killed or permanently disabled
is higher than if the person had not
been drinking.
Control of a Vehicle
The following three systems
help to control the vehicle while
driving —brakes, steering, and
accelerator. At times, as when
driving on snow or ice, it is easy to
ask more of those control systems
than the tires and road can provide.
Meaning, you can lose control of the
vehicle. See StabiliTrak
®System on
page 9‑70.
Adding non‐dealer accessories
can affect vehicle performance.
See Accessories and Modifications
on page 10‑3.
Braking
See Brake System Warning Light on
page 5‑27.
Braking action involves perception
time and reaction time. Deciding
to push the brake pedal is
perception time. Actually doing
it is reaction time.
Average reaction time is about
three‐fourths of a second. But that
is only an average. It might be less
with one driver and as long as two
or three seconds or more with
another. Age, physical condition,
alertness, coordination, and
eyesight all play a part. So do
alcohol, drugs, and frustration. But
even in three‐fourths of a second,
a vehicle moving at 100 km/h
(60 mph) travels 20 m (66 ft).
That could be a lot of distance in
an emergency, so keeping enough
space between the vehicle and
others is important.

Black plate (5,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-5
Steering in Emergencies
There are times when steering
can be more effective than braking.
For example, you come over a hill
and find a truck stopped in your
lane, or a car suddenly pulls out
from nowhere, or a child darts out
from between parked cars and stops
right in front of you. These problems
can be avoided by braking—if you
can stop in time. But sometimes you
cannot stop in time because there
is no room. That is the time for
evasive action —steering around
the problem.
The vehicle can perform very
well in emergencies like these.
First, apply the brakes. See Braking
on page 9‑3. It is better to remove
as much speed as possible from
a collision. Then steer around
the problem, to the left or right
depending on the space available.
An emergency like this requires
close attention and a quick decision.
If holding the steering wheel at
the recommended 9 and 3 o'clock
positions, it can be turned a full
180 degrees very quickly without
removing either hand. But you have
to act fast, steer quickly, and just as
quickly straighten the wheel once
you have avoided the object.
The fact that such emergency
situations are always possible is a
good reason to practice defensive
driving at all times and wear safety
belts properly.
Off-Road Recovery
The vehicle's right wheels can drop
off the edge of a road onto the
shoulder while driving.
If the level of the shoulder is
only slightly below the pavement,
recovery should be fairly easy. Ease
off the accelerator and then, if there
is nothing in the way, steer so that
the vehicle straddles the edge of
the pavement. Turn the steering
wheel 8 to 13 cm (3 to 5 in), about
one-eighth turn, until the right front
tire contacts the pavement edge.
Then turn the steering wheel to
go straight down the roadway.

Black plate (11,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-11
Scanning the Terrain
Off-road driving can take you over
many different kinds of terrain.
Be familiar with the terrain and
its many different features.
Surface Conditions:Off-roading
surfaces can be hard-packed dirt,
gravel, rocks, grass, sand, mud,
snow, or ice. Each of these surfaces
affects the vehicle's steering,
acceleration, and braking in different
ways. Depending on the surface,
slipping, sliding, wheel spinning,
delayed acceleration, poor traction,
and longer braking distances can
occur. Surface Obstacles:
Unseen or
hidden obstacles can be hazardous.
A rock, log, hole, rut, or bump can
startle you if you are not prepared
for them. Often these obstacles are
hidden by grass, bushes, snow,
or even the rise and fall of the
terrain itself.
Some things to consider:
.Is the path ahead clear?
.Will the surface texture change
abruptly up ahead?
.Does the travel take you uphill or
downhill?
.Will you have to stop suddenly
or change direction quickly?
When driving over obstacles or
rough terrain, keep a firm grip on
the steering wheel. Ruts, troughs,
or other surface features can jerk
the wheel out of your hands. When driving over bumps, rocks,
or other obstacles, the wheels can
leave the ground. If this happens,
even with one or two wheels, you
cannot control the vehicle as well or
at all.
Because you will be on an unpaved
surface, it is especially important to
avoid sudden acceleration, sudden
turns, or sudden braking.
Off-roading requires a different kind
of alertness from driving on paved
roads and highways. There are no
road signs, posted speed limits,
or signal lights. Use good judgment
about what is safe and what is not.

Black plate (15,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-15
Driving Downhill
When off-roading takes you
downhill, consider:
.How steep is the downhill? Will I
be able to maintain vehicle
control?
.What is the surface like?
Smooth? Rough? Slippery?
Hard-packed dirt? Gravel?
.Are there hidden surface
obstacles? Ruts? Logs?
Boulders?
.What is at the bottom of the hill?
Is there a hidden creek bank or
even a river bottom with large
rocks?
If you decide you can go down
a hill safely, try to keep the vehicle
headed straight down. Use a low
gear so engine drag can help the
brakes so they do not have to do all
the work. Descend slowly, keeping
the vehicle under control at all
times.
{WARNING
Heavy braking when going
down a hill can cause your
brakes to overheat and fade.
This could cause loss of control
and a serious accident. Apply the
brakes lightly when descending a
hill and use a low gear to keep
vehicle speed under control.
Things not to do when driving down
a hill:
.When driving downhill, avoid
turns that take you across the
incline of the hill. A hill that is
not too steep to drive down
might be too steep to drive
across. The vehicle could
roll over.
.Never go downhill with the
transmission in N (Neutral),
called free-wheeling. The brakes
will have to do all the work and
could overheat and fade.
Vehicles are much more likely to
stall when going uphill, but if it
happens when going downhill:
1. Stop the vehicle by applying the regular brakes and apply the
parking brake.
2. Shift to P (Park) and, while still braking, restart the engine.
3. Shift back to a low gear, release the parking brake, and drive
straight down.
4. If the engine will not start, get out and get help.

Black plate (19,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-19
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep‐standing or flowing water.
{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.(Continued)
WARNING (Continued)
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.