
Black plate (27,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Seats and Restraints 3-27
rollover event, roof-rail airbag
deployment is determined by the
direction of the roll.
What Makes an Airbag
Inflate?
In a deployment event, the sensing
system sends an electrical signal
triggering a release of gas from the
inflator. Gas from the inflator fills the
airbag causing the bag to break out
of the cover and deploy. The inflator,
the airbag, and related hardware are
all part of the airbag module.
Frontal airbag modules are located
inside the steering wheel and
instrument panel. For vehicles with
seat‐mounted side impact airbags,
there are airbags modules in the
side of the front seatbacks closest
to the door. For vehicles with
roof-rail airbags, there are airbag
modules in the ceiling of the vehicle,
near the side windows that have
occupant seating positions.
How Does an Airbag
Restrain?
In moderate to severe frontal or
near frontal collisions, even belted
occupants can contact the steering
wheel or the instrument panel. In
moderate to severe side collisions,
even belted occupants can contact
the inside of the vehicle.
Airbags supplement the protection
provided by safety belts. Frontal
airbags distribute the force of the
impact more evenly over the
occupant's upper body, stopping
the occupant more gradually.
Seat‐mounted side impact and
roof-rail airbags distribute the force
of the impact more evenly over the
occupant's upper body.
Rollover capable roof-rail airbags
are designed to help contain the
head and chest of occupants in the
outboard seating positions in the
first and second rows. The rollover
capable roof-rail airbags are
designed to help reduce the risk offull or partial ejection in rollover
events, although no system can
prevent all such ejections.
But airbags would not help in
many types of collisions, primarily
because the occupant's motion
is not toward those airbags. See
When Should an Airbag Inflate? on
page 3‑25
for more information.
Airbags should never be regarded
as anything more than a supplement
to safety belts.
What Will You See after
an Airbag Inflates?
After the frontal airbags and
seat-mounted side impact airbags
inflate, they quickly deflate, so
quickly that some people may not
even realize an airbag inflated.
Roof-rail airbags may still be at least
partially inflated for some time after
they deploy. Some components of
the airbag module may be hot for
several minutes. For location of the
airbag modules, see What Makes
an Airbag Inflate? on page 3‑27.

Black plate (30,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
3-30 Seats and Restraints
Child age 1 to 12. A child
age 1 to 12 must ride in the front
seat because:
.My vehicle has no rear seat;
.Although children ages 1 to 12
ride in the rear seat(s) whenever
possible, children ages 1 to 12
sometimes must ride in the front
because no space is available in
the rear seat(s) of my vehicle; or
.The child has a medical
condition which, according to
the child's physician, makes it
necessary for the child to ride in
the front seat so that the driver
can constantly monitor the
child's condition.
Medical Condition. A passenger
has a medical condition which,
according to his or her physician:
.Causes the passenger airbag to
pose a special risk for the
passenger; and
.Makes the potential harm from
the passenger airbag in a crash
greater than the potential harm from turning off the airbag and
allowing the passenger, even if
belted, to hit the instrument
panel or windshield in a crash.
{WARNING
If the right front passenger airbag
is turned off for a person who is
not in a risk group identified by
the national government, that
person will not have the extra
protection of an airbag. In a
crash, the airbag will not be able
to inflate and help protect the
person sitting there. Do not turn
off the passenger airbag unless
the person sitting there is in a risk
group.
United States
Canada and Mexico

Black plate (37,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Seats and Restraints 3-37
WARNING (Continued)
proper service procedures, and
make sure the person performing
work for you is qualified to do so.
Adding Equipment to the
Airbag-Equipped Vehicle
Q: Is there anything I might addto or change about the vehicle
that could keep the airbags
from working properly?
A: Yes. If you add things that
change your vehicle's frame,
bumper system, height, front end
or side sheet metal, they may
keep the airbag system from
working properly. Changing or
moving any parts of the front
seats, safety belts, the airbag
sensing and diagnostic module,
steering wheel, instrument
panel, roof-rail airbag modules,
ceiling headliner or pillar garnish
trim, overhead console, front sensors, side impact sensors,
or airbag wiring can affect the
operation of the airbag system.
In addition, the vehicle may have
a passenger sensing system
for the right front passenger's
position, which includes sensors
that are part of the passenger's
seat. The passenger sensing
system may not operate properly
if the original seat trim is
replaced with non-GM covers,
upholstery or trim, or with
GM covers, upholstery or
trim designed for a different
vehicle. Any object, such as an
aftermarket seat heater or a
comfort enhancing pad or
device, installed under or on top
of the seat fabric, could also
interfere with the operation of
the passenger sensing system.
This could either prevent proper
deployment of the passenger
airbag(s) or prevent the
passenger sensing system
from properly turning off the
passenger airbag(s). See
Passenger Sensing System on
page 3‑32.
If you have any questions
about this, you should contact
Customer Assistance before you
modify your vehicle. The phone
numbers and addresses for
Customer Assistance are in
Step Two of the Customer
Satisfaction Procedure in
this manual. See
Customer
Satisfaction Procedure (U.S.
and Canada) on page 13‑1 or
Customer Satisfaction
Procedure (Mexico) on
page 13‑3.
If the vehicle has rollover
roof-rail airbags, see Different
Size Tires and Wheels on
page 10‑70 for additional
important information.

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Storage 4-1
Storage
Storage Compartments
Instrument Panel Storage . . . . . 4-1
Glove Box . . . . . . . . . . . . . . . . . . . . 4-1
Cupholders . . . . . . . . . . . . . . . . . . . 4-1
Center Console Storage . . . . . . 4-2
Storage
Compartments
Instrument Panel Storage
For vehicles equipped with an
instrument panel storage area, it is
located above the glove box.
Access the storage area by
pressing and holding in the driver
side of the handle and pull out on
the exposed portion of the handle.
Glove Box
Lift up on the glove box lever to
open it.
Cupholders
If equipped, there are cupholders on
the center console and the rear of
the center console, also in the rear
seat armrest.
Pull the cover down on the rear of
the center console to access the
cupholders in the rear of the center
console.
Pull the rear seat armrest down to
access the cupholders.

Black plate (11,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-11
Ashtrays
The vehicle may have a front
ashtray located near the center of
the instrument panel. Pull on the
door to open it. The ashtray may
have a cigarette lighter.
Notice:If papers, pins, or other
flammable items are put in the
ashtray, hot cigarettes or other
smoking materials could ignite
them and possibly damage the
vehicle. Never put flammable
items in the ashtray.
To remove the ashtray, open the
door and pull the ashtray bin toward
you. To replace the ashtray, insert
the ashtray bin inside the ashtray
door and press down until it
engages.
Warning Lights,
Gauges, and
Indicators
Warning lights and gauges can
signal that something is wrong
before it becomes serious enough
to cause an expensive repair or
replacement. Paying attention to the
warning lights and gauges could
prevent injury.
Warning lights come on when there
could be a problem with a vehicle
function. Some warning lights come
on briefly when the engine is started
to indicate they are working. Gauges can indicate when there
could be a problem with a vehicle
function. Often gauges and warning
lights work together to indicate a
problem with the vehicle.
When one of the warning lights
comes on and stays on while
driving, or when one of the gauges
shows there may be a problem,
check the section that explains what
to do. Follow this manual's advice.
Waiting to do repairs can be costly
and even dangerous.

Black plate (13,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-13
For vehicles with a DURAMAX®
Diesel engine, see the DURAMAX®
Diesel Supplement for more
information.
For vehicles with a Hybrid, see the
Hybrid Supplement for more
information.
Speedometer
The speedometer shows the
vehicle's speed in either kilometers
per hour (km/h) or miles per
hour (mph).
Odometer
The odometer shows how far the
vehicle has been driven, in either
kilometers or miles.
Engine Hour Meter Display
The Driver Information Center (DIC)
can also display the number of
hours the engine has run. To display
the engine hours, turn the ignition
off, then press and hold the reset
button for at least four seconds.The hour meter displays for up to
30 seconds, or until the ignition is
turned on. See
Driver Information
Center (DIC) on page 5‑30 for more
information.
Trip Odometer
The trip odometer shows how far
the vehicle has been driven since
the trip odometer was last set
to zero.
Press the reset button, located on
the instrument panel cluster next to
the voltmeter, to toggle between
the trip odometer and the regular
odometer. Holding the reset button
for approximately one second while
the trip odometer is displayed will
reset it. To display the odometer reading
with the ignition off, press the reset
button.
See
Driver Information Center (DIC)
on page 5‑30 for more information.
Tachometer
The tachometer displays the engine
speed in revolutions per minute
(rpm). For a description of how
Grade Braking affects vehicle
speed while the Tow/Haul Mode is
activated, see Tow/Haul Mode on
page 9‑39 for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.

Black plate (17,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-17
When the engine is running, this
gauge shows the condition of the
charging system. The gauge can
transition from a higher to lower or a
lower to higher reading. This is
normal. If the vehicle is operating
outside the normal operating range,
the charging system light comes on.
SeeCharging System Light on
page 5‑22 for more information. The
voltmeter gauge may also read
lower when in fuel economy mode.
This is normal.
Readings outside the normal
operating range can also occur
when a large number of electrical
accessories are operating in the
vehicle and the engine is left idling
for an extended period. This
condition is normal since the
charging system is not able to
provide full power at engine idle. As engine speeds are increased,
this condition should correct itself as
higher engine speeds allow the
charging system to create maximum
power.
The vehicle can only be driven for a
short time with the readings outside
the normal operating range. If the
vehicle must be driven, turn off all
accessories, such as the radio and
air conditioner.
Readings outside the normal
operating range indicate a possible
problem in the electrical system.
Have the vehicle serviced as soon
as possible.Safety Belt Reminders
Driver Safety Belt Reminder
Light
There is a driver safety belt
reminder light on the instrument
panel cluster.
When the vehicle is started, this
light flashes and a chime may come
on to remind the driver to fasten
their safety belt. Then the light stays
on solid until the belt is buckled.
This cycle my continue several
times if the driver remains or
becomes unbuckled while the
vehicle is moving.
If the driver safety belt is buckled,
neither the light nor the chime
comes on.

Black plate (24,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
5-24 Instruments and Controls
The following may correct an
emission system malfunction:
.Check that the fuel cap is fully
installed. SeeFilling the Tank on
page 9‑72. The diagnostic
system can determine if the
fuel cap has been left off or
improperly installed. A loose or
missing fuel cap allows fuel to
evaporate into the atmosphere.
A few driving trips with the cap
properly installed should turn the
light off.
.Check that good quality fuel is
used. Poor fuel quality causes
the engine not to run as
efficiently as designed and may
cause stalling after start-up,
stalling when the vehicle is
changed into gear, misfiring,
hesitation on acceleration,
or stumbling on acceleration.
These conditions might go away
once the engine is warmed up. If one or more of these conditions
occurs, change the fuel brand used.
It will require at least one full tank of
the proper fuel to turn the light off.
See
Recommended Fuel on
page 9‑68.
If none of the above have made
the light turn off, your dealer can
check the vehicle. The dealer has
the proper test equipment and
diagnostic tools to fix any
mechanical or electrical problems
that might have developed.Emissions Inspection and
Maintenance Programs
Some local governments may have
programs to inspect the on-vehicle
emission control equipment. For
the inspection, the emission system
test equipment is connected
to the vehicle’s Data Link
Connector (DLC).
The DLC is under the instrument
panel to the left of the steering
wheel. See your dealer if assistance
is needed.
The vehicle may not pass
inspection if:
.The malfunction indicator lamp is
on with the engine running, or if
the light does not come on when
the ignition is turned to ON/RUN
while the engine is off. See
your dealer for assistance in
verifying proper operation of the
malfunction indicator lamp.
.The OBD II (On-Board
Diagnostics) system
determines that critical
emission control systems have
not been completely diagnosed.