2021 GMC SIERRA light

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 33
The security light, in the instrument cluster,
comes on if there is a problem with arming
or disarming the theft-deterrent system.
The system has one or more RKE
transmitters matched to an immobilizer
control unit in your vehicle. Only a correctly
matched RKE transmitter will start the
vehicle. If the transmitter is ever damaged,
you may not be able to start your vehicle.
When trying to start the vehicle, the
security light may come on briefly when the
ignition is turned on. If the engine does not
start and the security light stays on, there is
a problem with the system. Turn the
ignition off and try again.
If the vehicle will not change ignition modes
(ACC/ACCESSORY, on, off), and the RKE
transmitter appears to be undamaged, try
another transmitter. Or, you may try placing
the transmitter in the transmitter pocket
located in the center console. SeeRemote
Keyless Entry (RKE) System Operation (Key
Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013.
If the ignition mode will not change with
the other transmitter or with the
transmitter in the transmitter pocket, your
vehicle needs service. If the ignition does change modes, the first transmitter may be
faulty. See your dealer who can service the
theft-deterrent system and have a new RKE
transmitter programmed to the vehicle.
It is possible for the immobilizer system to
learn new or replacement RKE transmitters.
Up to eight transmitters can be
programmed for the vehicle. To program
additional transmitters, see "Programming
Transmitters to the Vehicle" under
Remote
Keyless Entry (RKE) System Operation (Key
Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013
Do not leave the transmitter or device that
disarms or deactivates the vehicle theft
system in the vehicle.
When equipped with a key, if the engine
still does not start, and the key appears to
be undamaged, try another ignition key.
It may be necessary to check the fuse. See
Fuses and Circuit Breakers 0353. 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. It is possible for the
immobilizer system to learn new or
replacement keys. Up to eight keys can be
programmed for the vehicle. To program additional keys, see
Keys (Key Access)07or
Keys (Keyless Access) 09. Do not leave the
key or device that disarms or deactivates
the vehicle theft system in the vehicle.
See your dealer to get a new key blank cut
exactly as the ignition key that operates the
system.
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.
Standard Mirrors
The passenger side mirror is convex shaped.
A convex mirror's surface is curved so more
can be seen from the driver seat.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
34 Keys, Doors, and Windows
Trailer-Tow Mirrors
The upper portion of both the driver and
passenger mirrors is flat.
The lower portion of both the driver and
passenger mirrors is convex. A convex
mirror’s surface is curved so more can be
seen from the driver seat. The lower portion
is adjusted manually.
Manual Mirrors
If equipped, adjust manual mirrors by
moving the mirror up and down or left to
right to see a little of the side of the vehicle
and to have a clear view behind the vehicle.
Using hood-mounted air deflectors and
add-on convex mirror attachments could
decrease mirror performance.
Trailer-Tow Mirrors
Extending Mirrors
Trailer tow mirrors can extend out for better
visibility when towing a trailer.
Manual Extend :If equipped, grasp the
mirror housing firmly and pull back in one
motion, arching slightly toward the rear of
the vehicle.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 35
To return the mirror to its original position,
reverse the motion.
Power Extend :If equipped, press the power
extend button to fully extend the mirror.
Press again to retract.
Resetting the Power Extend Mirrors
Reset the power extend mirrors if:
.The mirrors are accidentally obstructed
while extending/retracting.
.The mirrors are accidentally manually
extended/retracted.
.The mirrors vibrate at normal driving
speeds. If a popping noise from the mirror is heard,
this sound is normal as the manual detents
are aligning after a manual extend/retract
operation has occurred.
Auxiliary Cargo Mirror Lamps
If equipped, cargo mirror lamps face
rearward to provide more light on the sides
of the vehicle, if needed. See
Exterior Cargo
Lamps 0144.
Advanced Trailering Vision System Side
Cameras
If equipped, the Advanced Trailering Vision
System side cameras are on the bottom of
the outside mirrors. See “Surround Vision
(360 Degrees)” underAssistance Systems for
Parking or Backing 0266.
Power Mirrors
To adjust each mirror:
1. Press
jor|to select the driver or
passenger side mirror. The indicator light
will illuminate.
2. Press the arrows 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.
4. Press
jor|again to deselect the
mirror.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
36 Keys, Doors, and Windows
Turn Signal Indicator
If equipped, the mirror has turn signal
indicator lights, which flash in the direction
of the turn or lane change.
Task Lighting
If equipped, task lighting projects light from
the outside mirrors to the sides of the
vehicle. SeeTask Lighting 0144.
Puddle Lamps
If equipped, puddle lamps project light from
the bottom of the mirror to the area of
ground below the driver and passenger
doors. See Entry Lighting 0146 and
Exit Lighting 0146.
Memory Mirrors
The vehicle may have memory mirrors. See
Memory Seats 049.
Lane Change Alert (LCA)
The vehicle may have LCA. See Lane Change
Alert (LCA) 0280.Folding Mirrors
Manual Folding Mirrors
If equipped, push the mirror toward the
vehicle to fold. 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.
Power Folding Mirrors
If equipped, pressgto power fold the
mirrors. Press again to unfold. Resetting the Power Folding Mirrors
Reset the power folding mirrors if:
.The mirrors are accidentally obstructed
while folding.
.The mirrors 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 noise may be heard
during the resetting of the power folding
mirrors. This sound is normal after a manual
folding operation.
Remote Mirror Folding
If equipped, press and holdQon the RKE
transmitter for approximately one second to
remotely fold the exterior mirrors. Press and
hold
Kon the RKE transmitter for
approximately one second to unfold. See
Remote Keyless Entry (RKE) System
Operation (Key Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
42 Keys, Doors, and Windows
Press2to engage the rear window
lockout feature. The indicator light is on
when engaged.
Press
2again to disengage.
Windows Express Movement
All windows can be opened without holding
the window switch. Press the switch down
fully and quickly release to express open the
window.
If equipped, pull the window switch up fully
and quickly release to express close the
window.
Briefly press or pull the window switch in
the same direction to stop that window’s
express movement.
Express Window Down
L: If equipped, this button will be on the
center stack.
Press and hold
Lto open all windows.
Release
Lto stop all movement.
Use the power window switches to close
each window.
Window Automatic Reversal System
The express-close feature will reverse
window movement if it comes in contact
with an object. Extreme cold or ice could
cause the window to auto-reverse. The
window will operate normally after the
object or condition is removed.
Automatic Reversal System Override
{Warning
If automatic reversal system override is
active, the window will not reverse
automatically. You or others could be
injured and the window could be
damaged. Before using automatic reversal
system override, make sure that all
people and obstructions are clear of the
window path.
When the engine is on, override the
automatic reversal system by pulling and
holding the window switch if conditions
prevent it from closing.
Programming the Power Windows
Programming may be necessary if the
vehicle battery has been disconnected or
discharged. If the window is unable to
express-up, program each express-close
window: 1. Close all doors.
2. Turn the ignition on or to ACC/ ACCESSORY.
3. Partially open the window to be programmed. Then close it and continue
to pull the switch briefly after the
window has fully closed.
4. Open the window and continue to press the switch briefly after the window has
fully opened.
Remote Window Operation
If equipped, this feature allows the windows
to be opened remotely. If enabled in vehicle
personalization, press and hold
Kon the
RKE transmitter. See Vehicle Personalization
0 131.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 43
Rear Windows
Power Sliding Rear Window
If equipped, the power sliding rear window
works when the ignition has been turned on
or to ACC/ACCESSORY, or Retained Accessory
Power (RAP) must be active. SeeRetained
Accessory Power (RAP) 0236.
.Press the switch to open the window.
.Pull the switch to close the window.
The power sliding rear window cannot be
operated manually.
Sun Visors
Pull the sun visor down to block glare.
If equipped, detach the sun visor from the
center mount to pivot to the side window
or to extend along the rod.
If equipped, there is a lighted mirror on the
sun visor. Lift the cover to open.
Roof
Sunroof
1. SLIDE Switch
2. TILT Switch
If equipped, the sunroof operates when the
ignition is on or in ACC/ACCESSORY, or when
Retained Accessory Power (RAP) is active.
See Retained Accessory Power (RAP) 0236.
Slide Switch
Express-Open/Express-Close : To
express-open the sunroof, fully press and
release
I(1). Press and releaseI(1) again
to stop the movement. To express-close the

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
44 Keys, Doors, and Windows
sunroof, fully press and releaseK(1).
Press and release
K(1) again to stop the
movement.
Open/Close (Manual Mode) : To open the
sunroof, press and hold
I(1). ReleaseI(1)
to stop the movement. Press and
hold
K(1) to close the sunroof.
Release
K(1) to stop the movement.
Tilt Switch
Vent : From the closed position, press
J(2)
to vent the sunroof. Press
K(2) to close
the vent.
When the sunroof is opened, an air deflector
will automatically raise. The air deflector will
retract when the sunroof is closed.
The sunroof also has a sunshade, which can
be pulled forward to block sun rays. The
sunshade must be opened and closed
manually.
Automatic Reversal System
The sunroof has an automatic reversal
system that is only active when the sunroof
is operated in express-close mode.
If an object is in the path while
express-closing, the reversal system will
detect an object, stop, and open the sunroof
slightly.
If frost or other conditions prevent closing,
override the feature by closing the sunroof
in manual mode. To stop movement, release
K(1).
Dirt and debris may collect on the sunroof
seal or in the track. This could cause an
issue with sunroof operation or noise. It could also plug the water drainage
system. Periodically open the sunroof and
remove any obstacles or loose debris. Wipe
the sunroof seal and roof sealing area using
a clean cloth, mild soap, and water. Do not
remove grease from the sunroof tracks.
If water is seen dripping into the water
drainage system, this is normal.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
52 Seats and Restraints
Obstructions
If something has blocked the driver seat
while recalling a memory position, the recall
may stop. Remove the obstruction and try
the recall again. If the memory position still
does not recall, see your dealer.
Heated and Ventilated Front
Seats
{Warning
If temperature change or pain to the skin
cannot be felt, the seat heater may cause
burns. To reduce the risk of burns, use
care when using the seat heater,
especially for long periods of time. Do
not place anything on the seat that
insulates against heat, such as a blanket,
cushion, cover, or similar item. This may
cause the seat heater to overheat. An
overheated seat heater may cause a burn
or may damage the seat.Heated and Ventilated Seat Buttons Shown,Heated Seat Buttons Similar
If equipped, the buttons are on the center
stack. To operate, the engine must be
running.
Press
Ior+to heat the driver or
passenger seatback only.
Press
Jorzto heat the driver or
passenger seat cushion and seatback.
Press
Cor{to ventilate the driver or
passenger seat.
The indicator light on the button comes on
when this feature is on. Press the button once for the highest
setting. With each press of the button, the
seat will change to the next lower setting,
and then to the off setting. The indicator
lights next to the buttons indicate three for
the highest setting and one for the lowest.
If the heated seats are on high for an
extended time, their level may automatically
be lowered.
Auto Heated Seats
When the vehicle is on, this feature will
automatically activate the heated seats at
the level required by the vehicle’s interior
temperature. The active high, medium, low,
or off heated seat level will be indicated by
the manual heated seat buttons on the
center stack. Use the manual heated seat
buttons on the center stack to turn auto
heated seats off. If the passenger seat is
unoccupied, the auto heated seats feature
will not activate that seat. The auto heated
seats feature can be programmed to always
be enabled when the vehicle is on. See
Vehicle Personalization
0131.