Page 57 of 556

Black plate (13,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Keys, Doors, and Windows 2-13
Immobilizer Operation
This vehicle has PASS-Key®III+
(Personalized Automotive Security
System) theft-deterrent system.
PASS-Key III+ is a passive
theft-deterrent system.
The system is automatically armed
when the key is removed from the
ignition.
The system is automatically
disarmed when the key is turned
to ON/RUN, ACC/ACCESSORY,
or START from the LOCK/OFF
position.
You do not have to manually arm or
disarm the system.
The security light will come on if
there is a problem with arming or
disarming the theft-deterrent
system.
When the PASS-Key III+ system
senses that someone is using the
wrong key, it prevents the vehicle
from starting. Anyone using a
trial-and-error method to start the vehicle will be discouraged because
of the high number of electrical key
codes.
If the engine does not start and the
security light on the instrument
panel cluster comes on when trying
to start the vehicle, there may be a
problem with the theft-deterrent
system. Turn the ignition off and try
again.
If the engine still does not start, and
the key appears to be undamaged,
try another ignition key. At this time,
you may also want to check the
fuse. See
Fuses and Circuit
Breakers on page 10‑44. If the
engine still does not start with the
other key, the vehicle needs service.
If the vehicle does start, the first key
may be faulty. See your dealer who
can service the PASS-Key III+ to
have a new key made.
It is possible for the PASS-Key III+
decoder to learn the transponder
value of a new or replacement key.
Up to 10 keys may be programmed for the vehicle. The following
procedure is for programming
additional keys only. If all the
currently programmed keys are lost
or do not operate, you must see
your dealer or a locksmith who can
service PASS-Key III+ to have keys
made and programmed to the
system.
See your dealer or a locksmith who
can service PASS-Key III+ to get a
new key blank cut exactly as the
ignition key that operates the
system.
To program the new additional key:
1. Verify that the new key has
a
1stamped on it.
2. Insert the original, already programmed key in the ignition
and start the engine. If the
engine will not start, see your
dealer for service.
3. After the engine has started, turn the key to LOCK/OFF, and
remove the key.
Page 58 of 556

Black plate (14,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
2-14 Keys, Doors, and Windows
4. Insert the new key to beprogrammed and turn it to the
ON/RUN position within
five seconds of turning the
ignition to the LOCK/OFF
position in Step 3.
The security light will turn off
once the key has been
programmed.
5. Repeat Steps 1 through 4 if additional keys are to be
programmed.
If you lose or damage your
PASS-Key III+ key, see your dealer
or a locksmith who can service
PASS-Key III+ to have a new
key made.
Do not leave the key or device
that disarms or deactivates the
theft-deterrent system in the vehicle.Exterior Mirrors
Convex Mirrors
{WARNING
A convex mirror can make things,
like other vehicles, look farther
away than they really are. If you
cut too sharply into the right lane,
you could hit a vehicle on the
right. Check the inside mirror or
glance over your shoulder before
changing lanes.
The passenger side mirror is convex
shaped. A convex mirror's surface is
curved so more can be seen from
the driver seat.
Manual Mirrors
If the vehicle has manual mirrors,
they can be adjusted by moving the
mirror up and down or left to right to
see a little of the side of the vehicle,
and have a clear view behind the
vehicle.
Using hood-mounted air deflectors
and add-on convex mirror
attachments could decrease mirror
performance.
Page 59 of 556

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.
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Black plate (16,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
2-16 Keys, Doors, and Windows
2. Press one of the four arrowslocated on the control pad to
move the mirror in the desired
direction.
3. Adjust each outside mirror so that a little of the vehicle and the
area behind it can be seen.
Keep the selector switch in the
center position when not adjusting
either outside mirror.Folding Mirrors
Crew Cab Premium Trim with
Power Folding Mirrors Shown, Other Models Similar
Power Folding
If equipped with power folding
mirrors:
1. Press (A) to fold the mirrors outto the driving position.
2. Press (B) to fold the mirrors in to the folded position. The mirrors may also include a
memory function that works with the
memory seats. See
Memory Seats
on page 3‑7 for more information.
Resetting the Power Folding
Mirrors
Reset the power folding mirrors if:
.The mirrors are accidentally
obstructed while folding.
.They are accidentally manually
folded/unfolded.
.The mirrors will not stay in the
unfolded position.
.The mirrors vibrate at normal
driving speeds.
Fold and unfold the mirrors one time
using the mirror controls to reset
them to their normal position.
A popping noise may be heard
during the resetting of the power
folding mirrors. This sound is normal
after a manual folding operation.
Page 61 of 556

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.
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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.
Page 63 of 556
Black plate (19,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Keys, Doors, and Windows 2-19
Windows
{WARNING
Leaving children, helpless adults,
or pets in a vehicle with the
windows closed is dangerous.
They can be overcome by the
extreme heat and suffer
permanent injuries or even death
from heat stroke. Never leave a
child, a helpless adult, or a pet
alone in a vehicle, especially with
the windows closed in warm or
hot weather.
The vehicle aerodynamics are
designed to improve fuel economy
performance. This may result in apulsing sound when a window is
partially open. To reduce the sound,
open another window or the sunroof
(if equipped).
Manual Windows
Turn the hand crank on each door
to manually raise or lower the
manual windows.
Page 64 of 556

Black plate (20,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
2-20 Keys, Doors, and Windows
Power Windows
{WARNING
Leaving children in a vehicle with
the keys is dangerous for many
reasons. Children or others could
be badly injured or even killed.
They could operate the power
windows or other controls or even
make the vehicle move. The
windows will function and they
could be seriously injured or killed
if caught in the path of a closing
window. Do not leave keys in a
vehicle with children.
When there are children in the
rear seat use the window lockout
button to prevent unintentional
operation of the windows.
Crew Cab Premium Trim Shown,Others Models Similar
The driver door has a switch
to control all windows. Each
passenger door has a switch to
control that window. The power
windows only work when the
ignition is in ON/RUN or ACC/
ACCESSORY, or when Retained
Accessory Power (RAP) is active.
See Retained Accessory Power
(RAP) on page 9‑29. Push the switch down to lower the
window, and pull up the front of the
switch to raise the window.
Express-down Windows
The express-down feature allow the
driver and front passenger windows
to be lowered without holding the
switch. Push the switch down to the
second detent, then release, to
activate the express-down mode.
The express-down mode can be
canceled at any time by pulling up
on the front of the switch. To open
the window partway, push the switch
down to the first detent until the
window is at the desired position.