2012 GMC SIERRA 1500 tow

Black plate (15,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Keys, Doors, and Windows 2-15
Trailer-Tow Mirrors
If the vehicle has towing mirrors,
they can be adjusted for a clearer
view of the objects behind you.
Manually pull out the mirror head to
extend it for better visibility when
towing a trailer.
The lower portion of the mirror is
convex. A convex mirror's surface is
curved to see more from the driver
seat. The convex mirror can be
adjusted manually to the driver
preferred position for better vision.
The mirror may have a turn signal
arrow that flashes in the direction of
the turn or lane change.
Power Mirrors
Crew Cab Premium Trim with
Power Folding Mirrors Shown, Other Models Similar
1. Press (A) or (B) to select the driver or passenger side mirror.
2. Press the arrows on the control pad to move the mirror up,
down, right, or left.
3. Adjust each outside mirror so that a little of the vehicle and the
area behind it can be seen.
4. Press either (A) or (B) again to deselect the mirror. The mirrors may also include a
memory function that works with the
memory seats. See
Memory Seats
on page 3‑7 for more information.
Crew Cab Up‐Level Trim without
Power Folding Mirrors
1. Move the selector switch located above the four-way control pad
to the left or right to choose
either the driver side or
passenger side mirror.

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 (18,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
2-18 Keys, Doors, and Windows
Interior Mirrors
Manual Rearview Mirror
To adjust the inside rearview mirror,
hold the rearview mirror in the
center and move it to view the area
behind the vehicle.
For vehicles with a manual rearview
mirror, push the tab forward for
daytime use and pull it for nighttime
use to avoid glare from the
headlamps from behind.
Vehicles with OnStar
®have three
control buttons at the bottom of the
mirror. See a dealer for more
information about OnStar and how
to subscribe to it. See OnStar
Overview on page 14‑1.
Automatic Dimming
Rearview Mirror
The vehicle may have an automatic
dimming inside rearview mirror.
To adjust the inside rearview mirror,
hold the rearview mirror in the
center and move it to view the area
behind the vehicle.
The automatic dimming rearview
mirror will automatically reduce the
glare from the headlamps from
behind. The dimming feature comes
on when the vehicle is started.
O(On/Off): Press to turn the
dimming feature on or off.
The vehicle may also have a Rear
Vision Camera (RVC). See Rear
Vision Camera (RVC) on page 9‑62
for more information. If the vehicle has a RVC,
the
Obutton for turning the
dimming feature on or off will
not be available.
Vehicles with OnStar have three
additional control buttons for the
OnStar system. See a dealer for
more information about OnStar and
how to subscribe to it. See OnStar
Overview on page 14‑1.
Cleaning the Mirror
Do not spray glass cleaner directly
on the mirror. Use a soft towel
dampened with water.

Black plate (10,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
3-10 Seats and Restraints
Remote Start Heated Seats
When it is cold outside, the heated
seats may turn on automatically
during a remote vehicle start. The
heated seats will be canceled when
the ignition is turned on. Press the
desired button to use the heated
seats after the vehicle is started.
The lights on the heated seat
buttons do not turn on during a
remote start.
The temperature performance of an
unoccupied seat may be reduced.
This is normal.
SeeRemote Vehicle Start on
page 2‑5.Rear Seats
Rear Seats (Extended
Cab Full Bench)
Folding the Rear Seat
Notice: Folding a rear seat with
the safety belts still fastened may
cause damage to the seat or the
safety belts. Always unbuckle the
safety belts and return them to
their normal stowed position
before folding a rear seat.
To fold the seat:
1. Pull up on the front of the seat cushion while pulling down on
the release strap under the seat
cushion.
2. Pull the seat cushion up until it latches with the seatback.
3. Pull forward on the seat cushion to make sure it is locked in
place.

Black plate (11,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Seats and Restraints 3-11
To unfold the seat:
1. Push the seat cushion rearwardwhile pulling the release strap
under the seat cushion. Pull the
seat cushion down until it
latches.
2. Pull up on the seat cushion to make sure it is locked in place.
Make sure the safety belts are
not twisted or caught in the seat
cushion.
{WARNING
A safety belt that is improperly
routed, not properly attached,
or twisted will not provide the
protection needed in a crash. The
person wearing the belt could be
seriously injured. After raising the
rear seatback, always check to be
sure that the safety belts are
properly routed and attached, and
are not twisted.
Rear Seats (All Split
Bench and Hybrid Full
Bench)
Folding Rear Seat
Either side of the rear seat can be
folded for added cargo space.
Notice: Folding a rear seat with
the safety belts still fastened may
cause damage to the seat or the
safety belts. Always unbuckle the
safety belts and return them to
their normal stowed position
before folding a rear seat.
Make sure that nothing is on
the seat.
To fold the seat, slowly pull the seat
cushion up. To return the seat to the normal
seating position, slowly pull the seat
cushion down.
Make sure the safety belts are not
twisted or caught in the seat
cushion.
{WARNING
A safety belt that is improperly
routed, not properly attached,
or twisted will not provide the
protection needed in a crash. The
person wearing the belt could be
seriously injured. After raising the
rear seatback, always check to
be sure that the safety belts are
properly routed and attached, and
are not twisted.

Black plate (16,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
3-16 Seats and Restraints
To unlatch the belt, push the button
on the buckle. The belt should
return to its stowed position.
Before a door is closed, be sure the
safety belt is out of the way. If a
door is slammed against a safety
belt, damage can occur to both the
safety belt and the vehicle.
Shoulder Belt Height Adjuster
The vehicle has a shoulder belt
height adjuster for the driver and
right front passenger.Adjust the height so the shoulder
portion of the belt is on the shoulder
and not falling off of it. The belt
should be close to, but not
contacting, the neck. Improper
shoulder belt height adjustment
could reduce the effectiveness of
the safety belt in a crash. See
How
to Wear Safety Belts Properly on
page 3‑13.Regular and Crew Cab
To move the adjuster down for
the regular and crew cabs,
squeeze the buttons (A) on the sides of the height adjuster and
move the height adjuster to the
desired position.
Extended Cab
On the extended cab, push down
on the release button (A) and move
the height adjuster to the desired
position.
You can move the adjuster up just
by pushing up on the shoulder belt
guide.

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 (36,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
3-36 Seats and Restraints
Additional Factors Affecting
System Operation
Safety belts help keep the
passenger in position on the
seat during vehicle maneuvers
and braking, which helps the
passenger sensing system maintain
the passenger airbag status.
See“Safety Belts” and“Child
Restraints” in the Index for
additional information about the
importance of proper restraint use.
If the shoulder portion of the belt is
pulled out all the way, the child
restraint locking feature will be
engaged. This may unintentionally
cause the passenger sensing
system to turn the airbag off for
some adult size occupants. If this
happens, let the belt go back all the
way and start again.
A thick layer of additional material,
such as a blanket or cushion,
or aftermarket equipment such as
seat covers, seat heaters, and seat
massagers can affect how well the
passenger sensing system operates. We recommend that
you not use seat covers or other
aftermarket equipment except when
approved by GM for your specific
vehicle. See
Adding Equipment to
the Airbag-Equipped Vehicle on
page 3‑37 for more information
about modifications that can affect
how the system operates.
The on indicator may be lit if an
object, such as a briefcase,
handbag, grocery bag, laptop or
other electronic device, is put on an
unoccupied seat. If this is not
desired, remove the object from
the seat.
{WARNING
Stowing of articles under the
passenger seat or between the
passenger seat cushion and
seatback may interfere with the
proper operation of the passenger
sensing system.
Servicing the
Airbag-Equipped Vehicle
Airbags affect how the vehicle
should be serviced. There are parts
of the airbag system in several
places around the vehicle. Your
dealer and the service manual have
information about servicing the
vehicle and the airbag system. To
purchase a service manual, see
Service Publications Ordering
Information on page 13‑16.
{WARNING
For up to 10 seconds after the
vehicle is turned off and the
battery is disconnected, an airbag
can still inflate during improper
service. You can be injured if you
are close to an airbag when it
inflates. Avoid yellow connectors.
They are probably part of the
airbag system. Be sure to follow
(Continued)