tailgate GMC SIERRA 2021 Owner's Manual

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Introduction 5
1. Tow/Haul Mode (On Some Models). SeeDriver Mode Control 0251.
Automatic Transfer Case Control (If
Equipped). See Four-Wheel Drive 0242.
Driver Mode Control 0251 (If Equipped).
2. Air Vents 0209.
3. Head-Up Display (HUD) 0128 (If
Equipped).
4. Turn Signal Lever. See Turn and
Lane-Change Signals 0143.
Windshield Wiper/Washer 0101.
5. Instrument Cluster 0106.
6. Shift Lever. See Automatic Transmission
0 239.
Range Selection Mode. See Manual Mode
0 241.
7. Light Sensor. See Automatic Headlamp
System 0142.
8. Infotainment Controls. See Overview
0 149.
9. Climate Control Systems 0204 (If
Equipped).
Dual Automatic Climate Control System
0 206 (If Equipped).
10. Heated and Ventilated Front Seats 052
(If Equipped). 11.ALane Keep Assist (LKA)
0281 (If
Equipped).
XPark Assist Switch (If Equipped). See
Assistance Systems for Parking or Backing
0 266.
hAuto Stop Disable Switch (If
Equipped). See Stop/Start System 0233.
5Power Release Tailgate (If
Equipped). See Tailgate023.
|Hazard Warning Flashers 0142.
gTraction Control/Electronic Stability
Control 0248.
ADC/AC Switch. See Power Outlets
0 102.
5Hill Descent Control Switch (If
Equipped). See Hill Descent Control (HDC)
0 250.
jPower Assist Steps 030 (If
Equipped).
LExpress Window Down Button (If
Equipped). See Power Windows 041.
Tow/Haul Mode 0242 (On Some
Models).
Exhaust Brake (If Equipped). See Duramax
Diesel Supplement. Power Take-Off (PTO) (If Equipped). See
Duramax Diesel Supplement.
12. Power Outlet (Alternating Current) (If Equipped). See Power Outlets0102.
13. Power Outlet (Direct Current) Power
Outlets 0102.
14. USB Port 0158.
15. Wireless Charging 0103 (If Equipped).
16. Trailer Brake Control Panel (If Equipped). See“Integrated Trailer Brake Control
System” underTowing Equipment 0296.
17. ENGINE START/STOP. See Ignition
Positions (Keyless Access) 0230 or
Ignition Positions (Key Access) 0229.
18. Steering Wheel Controls 0100 (If
Equipped).
Driver Information Center (DIC) Controls.
See Driver Information Center (DIC) (Base
Level) 0124 or
Driver Information Center (DIC) (Midlevel
and Uplevel) 0125.
19. Horn 0101.
20. Hood Release. See Hood0323.
21. Steering Wheel Adjustment 0100 (Out
of View).

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 7
Keys, Doors, and
Windows
Keys and Locks
Keys (Key Access) . . . . . . . . . . . . . . . . . . . . . . . . 7
Keys (Keyless Access) . . . . . . . . . . . . . . . . . . . . 9
Remote Keyless Entry (RKE) System . . . . 10
Remote Keyless Entry (RKE) SystemOperation (Key Access) . . . . . . . . . . . . . . . 10
Remote Keyless Entry (RKE) System Operation (Keyless Access) . . . . . . . . . . . . 13
Remote Vehicle Start . . . . . . . . . . . . . . . . . . . 20
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Power Door Locks . . . . . . . . . . . . . . . . . . . . . . . 22
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 22
Automatic Door Locks . . . . . . . . . . . . . . . . . . 22
Lockout Protection . . . . . . . . . . . . . . . . . . . . . . 22
Safety Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Doors
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Power Assist Steps . . . . . . . . . . . . . . . . . . . . . 30
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . . . . . . . . . . 31
Vehicle Alarm System . . . . . . . . . . . . . . . . . . . 31
Steering Column Lock . . . . . . . . . . . . . . . . . . . 32
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Immobilizer Operation . . . . . . . . . . . . . . . . . . 32
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 33
Manual Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 34
Trailer-Tow Mirrors . . . . . . . . . . . . . . . . . . . . . 34
Power Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 36
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 37
Automatic Dimming Mirror . . . . . . . . . . . . . 37
Blind Spot Mirrors . . . . . . . . . . . . . . . . . . . . . . 37
Reverse Tilt Mirrors . . . . . . . . . . . . . . . . . . . . . 38
Interior Mirrors
Interior Rearview Mirrors . . . . . . . . . . . . . . . 38
Manual Rearview Mirror . . . . . . . . . . . . . . . . 38
Automatic Dimming Rearview Mirror . . . 38
Rear Camera Mirror . . . . . . . . . . . . . . . . . . . . 38
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Manual Windows . . . . . . . . . . . . . . . . . . . . . . . 41
Power Windows . . . . . . . . . . . . . . . . . . . . . . . . 41
Rear Windows . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Sun Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Keys and Locks
Keys (Key Access)
{Warning
Leaving children in a vehicle with the
ignition key is dangerous and children or
others could be seriously injured or killed.
They could operate the power windows
or other controls or make the vehicle
move. The windows will function with
the keys in the ignition, and children or
others could be caught in the path of a
closing window. Do not leave children in
a vehicle with the ignition key.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 11
Other conditions can affect the performance
of the transmitter. SeeRemote Keyless Entry
(RKE) System 010.
/:Press and releaseQ, then immediately
press and hold
/until the turn signal
lamps flash or for at least four seconds. The
engine may be started from outside the
vehicle using the RKE transmitter. See
Remote Vehicle Start 020.
Q:Press to lock all doors.
If enabled, the turn signal lamps may flash
and/or the horn may sound on the second
press to indicate locking has occurred. If enabled, the horn chirps when
Qis
pressed again within three seconds. See
Vehicle Personalization 0131.
Pressing
Qarms the alarm system. See
Vehicle Alarm System 031.
If equipped with remote mirror folding,
pressing and holding
Qfor one second will
fold the mirrors, if enabled. See Vehicle
Personalization 0131.
K:Press once to unlock only the driver
door. If
Kis pressed again within
three seconds, all remaining doors unlock.
The interior lamps may come on and stay
on for 20 seconds or until the ignition is
turned on.
If enabled, the turn signal lamps flash twice
to indicate unlocking has occurred.
If enabled, the exterior lamps may turn on.
See Vehicle Personalization 0131.
Pressing
Kon the RKE transmitter disarms
the alarm system. See Vehicle Alarm System
0 31.
If equipped with remote mirror folding,
pressing and holding
Kfor one second will
unfold the mirrors, if enabled. See Vehicle
Personalization 0131. Press and hold
Kto remotely open the
windows, if enabled. See Vehicle
Personalization 0131.
x:Press twice quickly to release the
tailgate, if equipped.
7: Press and release to initiate the vehicle
locator. The turn signal lamps flash and the
horn sounds three times.
Press and hold
7for more than
three seconds to activate the panic alarm.
The turn signal lamps flash and the horn
sounds repeatedly for 30 seconds. The alarm
turns off when the ignition is turned on or
7is pressed again. The ignition must be off
for the panic alarm to work.
Programming Transmitters to the Vehicle
Only RKE transmitters programmed to this
vehicle will work. If a transmitter is lost or
stolen, a replacement can be purchased and
programmed through your dealer. Each
vehicle can have up to eight transmitters
programmed to it. See your dealer for
transmitter programming.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 13
2. Press and slide the battery down towardthe pocket of the transmitter in the
direction of the key ring. Do not use a
metal object
3. Remove the battery.
4. Insert the new battery, positive side facing up. Replace with a CR2032 or
equivalent battery.
5. Push together the transmitter back cover top side first, and then the bottom
toward the key ring.
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
The Keyless Access system allows for vehicle
entry when the transmitter is within 1 m
(3 ft). See “Keyless Access Operation” later
in this section.
The RKE transmitter functions may work up
to 60 m (197 ft) away from the vehicle.
Other conditions can affect the performance
of the transmitter. See Remote Keyless Entry
(RKE) System 010.
The key that is part of the RKE transmitter
can be used for all locks.
Remove the key by pressing the button on
the side of the RKE transmitter near the
bottom and pull the key out. Never pull the
key out without pressing the button.
See your dealer if a new transmitter is
needed./: Press and releaseQ, then immediately
press and hold
/until the turn signal
lamps flash or for at least four seconds. The
engine may be started from outside the
vehicle using the RKE transmitter. See
Remote Vehicle Start 020.
Q:Press to lock all doors and the tailgate,
if equipped.
If enabled, the turn signal lamps flash and/
or the horn may sound on the second press
to indicate locking has occurred. If enabled,
the horn chirps when
Qis pressed again
within three seconds. See Vehicle
Personalization 0131.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
14 Keys, Doors, and Windows
If the driver door is open whenQis
pressed, all doors will lock and then the
driver door will immediately unlock,
if enabled. See Vehicle Personalization 0131.
If the passenger door is open when
Qis
pressed, all doors lock.
Pressing
Qarms the alarm system. See
Vehicle Alarm System 031.
If equipped with remote mirror folding,
pressing and holding
Qfor one second will
fold the mirrors, if enabled. See Vehicle
Personalization 0131.
K:Press once to unlock only the driver
door. If
Kis pressed again within
three seconds, all remaining doors and the
tailgate unlock. The interior lamps may
come on and stay on for 20 seconds or until
the ignition is turned on.
If enabled, the turn signal lamps flash twice
to indicate unlocking has occurred.
If enabled, the exterior lamps may turn on.
See Vehicle Personalization 0131.
Pressing
Kon the RKE transmitter disarms
the alarm system. See Vehicle Alarm System
0 31. If equipped with remote mirror folding,
pressing and holding
Kfor one second will
unfold the mirrors, if enabled. See Vehicle
Personalization 0131.
Press and hold
Kuntil the windows fully
open, if remote window operation is
enabled. See Vehicle Personalization 0131.
x:Press twice quickly to release the
tailgate, if equipped.
7: Press and release to initiate vehicle
locator. The turn signal lamps flash and the
horn sounds three times.
Press and hold
7for more than
three seconds to activate the panic alarm.
The turn signal lamps flash and the horn
sounds repeatedly for 30 seconds. The alarm
turns off when the ignition is turned on or
7is pressed again. The ignition must be off
for the panic alarm to work.
Keyless Access Operation
The Keyless Access system allows for doors
and the tailgate to be accessed without
pressing the RKE transmitter button. The RKE
transmitter must be within 1 m (3 ft) of the tailgate or door being opened. If the vehicle
has this feature, there will be a button on
the outside door handles.
Keyless Access can be programmed to
unlock all doors on the first lock/unlock
press from the driver door. Keyless
Unlocking can also be turned off. See
Vehicle
Personalization 0131.
If equipped with memory seats, RKE
transmitters 1 and 2 are linked to seating
positions of memory 1 or 2. See Memory
Seats 049.
Keyless Unlocking/Locking from the
Driver Door
When the doors are locked and the RKE
transmitter is within 1 m (3 ft) of the door
handle, pressing the lock/unlock button on
the driver door handle will unlock the driver
door. If the lock/unlock button is pressed
again within five seconds, all passenger
doors and the tailgate will unlock.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 15
Driver Side Shown, Passenger Side Similar
Pressing the lock/unlock button will cause
all doors to lock if any of the following
occur:
.It has been more than five seconds since
the first lock/unlock button press.
.Two lock/unlock button presses were
used to unlock all doors.
.Any vehicle door has been opened and all
doors are now closed.
Keyless Unlocking/Locking from the
Passenger Doors
When the doors are locked and the RKE
transmitter is within 1 m (3 ft) of the door
handle, pressing the lock/unlock button on a
passenger door handle will unlock all doors. Pressing the lock/unlock button will cause
all doors to lock if any of the following
occur:
.The lock/unlock button was used to
unlock all doors.
.Any vehicle door has been opened and all
doors are now closed.
Disable/Enable Keyless Unlocking of Exterior
Door Handles and Tailgate
If equipped, keyless unlocking of the exterior
door handles and tailgate can be disabled
and enabled.
Disabling Keyless Unlocking:
With the vehicle off, press and hold
Qand
Kon the RKE transmitter at the same time
for approximately three seconds. The turn
signal lamps will flash four times quickly to
indicate access is disabled. Using any
exterior handle to unlock the doors or open
the tailgate will cause the turn signal lamps
to flash four times quickly, indicating access
is disabled. If disabled, disarm the alarm
system before starting the vehicle. Enabling Keyless Unlocking:
With the vehicle off, press and hold
Qand
Kon the RKE transmitter at the same time
for approximately three seconds. The turn
signal lamps will flash twice quickly to
indicate access is enabled.
Passive Locking
This feature will lock the vehicle several
seconds after all doors are closed, if the
vehicle is off and at least one RKE
transmitter has been removed from the
interior, or none remain in the interior.
If other electronic devices interfere with the
RKE transmitter signal, the vehicle may not
detect the RKE transmitter inside the vehicle.
If passive locking is enabled, the doors may
lock with the RKE transmitter inside the
vehicle. Do not leave the RKE transmitter in
an unattended vehicle.
To customize the doors to automatically lock
when exiting the vehicle, see “Remote Lock,
Unlock, Start” underVehicle 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 21
Door Locks
{Warning
Unlocked doors can be dangerous.
.Passengers, especially children, can
easily open the doors and fall out of a
moving vehicle. The doors can be
unlocked and opened while the vehicle
is moving. The chance of being thrown
out of the vehicle in a crash is
increased if the doors are not locked.
So, all passengers should wear seat
belts properly and the doors should be
locked whenever the vehicle is driven.
.Young children who get into unlocked
vehicles may be unable to get out.
A child can be overcome by extreme
heat and can suffer permanent injuries
or even death from heat stroke.
Always lock the vehicle whenever
leaving it.
.Outsiders can easily enter through an
unlocked door when you slow down
or stop the vehicle. Locking the doors
can help prevent this from happening.There are several ways to lock and unlock
the vehicle.
From outside:
.Use the Remote Keyless Entry (RKE)
transmitter.
.Use Keyless Access, if equipped.
.Use the key in the driver door or the
passenger door, if equipped.
From inside, use the power door locks or the
manual door locks. To lock the door with
the manual door locks, push down on the
manual lock knob.
From inside, pull the door handle once to
unlock the door. Pull the handle again to
open the door.
See Vehicle Alarm System 031. Keyless Access
If equipped, the remote key must be within
1 m (3 ft) of the tailgate or door being
opened or locked. Press the button on the
door handle to open. See
“Keyless Access
Operation” inRemote Keyless Entry (RKE)
System Operation (Key Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013.
Free-Turning Locks
The door key lock cylinder turns freely when
either the wrong key is used, or the correct
key is not fully inserted. The free-turning
door lock feature prevents the lock from
being forced open. To reset the lock, turn it
to the vertical position with the correct key

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 23
Lockout Protection can be manually
overridden with the driver door open by
pressing and holding
Qon the power door
lock switch.
Open Door Anti-Lockout
If equipped, the Open Door Anti-Lockout is
turned on and the vehicle is off, the driver
door is open, and locking is requested, all
the doors will lock and the driver door will
unlock. The Open Door Anti-Lockout feature
can be turned on or off. See Vehicle
Personalization 0131.
Safety Locks
The rear door safety locks prevent
passengers from opening the rear doors
from inside the vehicle.
The safety lock is on the inside edge of the
rear doors. To use the safety lock:
1. Move the lever down to the lock position.
2. Close the door.
3. Do the same for the other rear door.
To open a rear door when the safety lock
is on: 1. Unlock the door by activating the inside handle, by pressing the power door
unlock switch, or by using the Remote
Keyless Entry (RKE) transmitter.
2. Open the door from the outside. When the safety lock is enabled, adults and
older children will not be able to open the
rear door from the inside. Cancel the safety
locks to enable the doors to open from the
inside.
To cancel the safety lock:
1. Unlock the door and open it from the outside.
2. Move the lever up to unlock. Do the same for the other door.Doors
Tailgate
Manual Tailgate
{Warning
It is extremely dangerous to ride on the
tailgate, even when the vehicle is
operated at low speeds. People riding on
the tailgate can easily lose their balance
and fall in response to vehicle maneuvers.
Falling from a moving vehicle may result
in serious injuries or death. Do not allow
people to ride on the tailgate. Be sure
everyone in your vehicle is in a seat and
using a seat belt properly.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
24 Keys, Doors, and Windows
Use the key to unlock the tailgate.
Open the tailgate by lifting up on its handle
while pulling the tailgate down.
To shut the tailgate, firmly push it upward
until it latches.
After closing the tailgate, pull it back to be
sure it is latched securely.
Some tailgates have an electric latch. If the
battery is disconnected or has low voltage,
the tailgate will not open. The tailgate will
resume operation when the battery is
reconnected or recharged.
Power Release Tailgate
{Warning
Make sure there is no one in the way of
the power tailgate as it is opening and
closing, and keep hands away from the
tailgate hinges when in use. You or
others could be injured if caught in the
path of the power tailgate or tailgate
hinges.
Caution
To avoid damage to the tailgate, make
sure the area behind the tailgate is clear
before opening it.
In the case of a dead battery, the tailgate
can be opened manually. Contact your
dealer or Roadside Assistance.
If equipped, to lock or unlock the tailgate,
use the RKE transmitter or the key. See
Remote Keyless Entry (RKE) System
Operation (Key Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013.
The vehicle must be in P (Park).
To open the tailgate:
.Pressxtwice quickly on the RKE
transmitter until the tailgate moves.
.Press5on the center stack.
.Press the touch pad on the tailgate
handle after unlocking all doors. Use the
top of the tailgate to pull against if

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Keys, Doors, and Windows 25
assistance is required. If equipped with
Keyless Access, a locked tailgate can be
opened if the RKE transmitter is within
1 m (3 ft).
To close the tailgate, firmly push it upward
until it latches. Pull it back to be sure it is
latched securely.
Power Tailgate
{Warning
Make sure there is no one in the way of
the power tailgate as it is opening and
closing, and keep hands away from the
tailgate hinges when in use. You or
others could be injured if caught in the
path of the power tailgate or tailgate
hinges.
Caution
To avoid damage to the tailgate, make
sure the area behind the tailgate is clear
before opening it. If equipped with a power open/close
tailgate, the tailgate can be opened or
closed in several ways. To open the tailgate,
do one of the following:
.Pressxtwice quickly on the RKE
transmitter until the tailgate moves. See
Remote Keyless Entry (RKE) System
Operation (Key Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013.
If equipped with Keyless Access, a locked
tailgate can be opened if the RKE
transmitter is within 1 m (3 ft).
.Press5on the center stack.
.Press the touch pad on the tailgate
handle after unlocking all doors.
To close the tailgate, do one of the
following:
.Pressxon the RKE transmitter once,
then quickly press and hold
xuntil the
tailgate completely closes. If
xis
released prior to it being fully closed, the
tailgate will reopen.