2021 GMC SIERRA window

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 2/18/21
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Keys, Doors, and Windows . . . . . . . . . . . . . . . 7
Seats and Restraints . . . . . . . . . . . . . . . . . . . . . 45
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Instruments and Controls . . . . . . . . . . . . . . . 99
Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Infotainment System . . . . . . . . . . . . . . . . . . . 148
Climate Controls . . . . . . . . . . . . . . . . . . . . . . . 204
Driving and Operating . . . . . . . . . . . . . . . . . . 211
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
Service and Maintenance . . . . . . . . . . . . . . 408
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . 423
Customer Information . . . . . . . . . . . . . . . . . . 428
Reporting Safety Defects . . . . . . . . . . . . . . . 436
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
Connected Services . . . . . . . . . . . . . . . . . . . . . 445
Index . . . . . . . . . . . . . . . . . . . . . . . . . . 448
Introduction
The names, logos, emblems, slogans, vehicle
model names, and vehicle body designs
appearing in this manual including, but not
limited to, GM, the GM logo, GMC, the GMC
Truck Emblem, SIERRA, and DENALI are
trademarks and/or service marks of General
Motors LLC, its subsidiaries, affiliates,
or licensors.
For vehicles first sold in Canada, substitute
the name“General Motors of Canada
Company” for GMC Division wherever it
appears in this manual. This manual describes features that may or
may not be on the vehicle because of
optional equipment that was not purchased
on the vehicle, model variants, country
specifications, features/applications that may
not be available in your region, or changes
subsequent to the printing of this owner’s
manual.
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement
for additional and specific information on
this engine.
Refer to the purchase documentation
relating to your specific vehicle to confirm
the features.
Keep this manual in the vehicle for quick
reference.
Litho in U.S.A.
Part No. 84550392 C Third Printing©2021 General Motors LLC. All Rights Reserved.

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
8 Keys, Doors, and Windows
{Warning
If the key is unintentionally rotated while
the vehicle is running, the ignition could
be moved out of the RUN position. This
could be caused by heavy items hanging
from the key ring, or by large or long
items attached to the key ring that could
be contacted by the driver or steering
wheel. If the ignition moves out of the
RUN position, the engine will shut off,
braking and steering power assist may be
impacted, and airbags may not deploy.
To reduce the risk of unintentional
rotation of the ignition key, do not
change the way the ignition key and
Remote Keyless Entry (RKE) transmitter,
if equipped, are connected to the
provided key rings.
The ignition key and key rings, and RKE
transmitter, if equipped, are designed to
work together as a system to reduce the
risk of unintentionally moving the key out
of the RUN position. The ignition key has a
small hole to allow attachment of the
provided key ring. It is important that any replacement ignition keys have a small hole.
See your dealer if a replacement key is
required.
The combination and size of the rings that
came with your keys were specifically
selected for your vehicle. The rings are
connected to the key like two links of a
chain to reduce the risk of unintentionally
moving the key out of the RUN position. Do
not add any additional items to the ring
attached to the ignition key. Attach
additional items only to the second ring,
and limit added items to a few essential
keys or small, light items no larger than an
RKE transmitter.
Interference from radio-frequency
identification (RFID) tags may prevent the
key from starting the vehicle. Keep RFID
tags away from the key when starting the
vehicle.
The key is used for the ignition, all door
locks, and the glove box.
If equipped with memory seats, keys 1 and 2
are linked to seating positions of memory 1
or 2. See
Memory Seats 049.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 9
Programming Keys
Follow these procedures to program up to
eight keys to the vehicle.
Programming with Two Recognized Keys
To program a new key:1. Insert the original, already programmed key in the ignition and turn the
ignition on.
2. Turn the ignition off, and remove the key.
3. Quickly, within five seconds, insert the second original already programmed key
in the ignition and turn the ignition on.
4. Turn the ignition off, and remove the key.
5. Insert the key to be programmed and turn the ignition on within five seconds.
6. After a few seconds, the security light will turn off once the key has been
programmed.
7. Repeat Steps 1–5 if additional keys are to be programmed.
If a key is lost or damaged, see your dealer
to have a new key made. Programming without Recognized Keys
Program a new key to the vehicle when a
recognized key is not available. Canadian
regulations require that owners see their
dealer.
If two currently recognized keys are not
available, follow this procedure to program
the first key.
This procedure will take approximately
30 minutes to complete for the first key.
The vehicle must be off and all of the keys
you wish to program must be with you.
1. Insert the new vehicle key into the ignition.
2. Turn the ignition on. The security light will come on.
3. Wait 10 minutes until the security light turns off.
4. Turn the ignition off.
5. Repeat Steps 2–4 two more times. After the third time, turn the ignition on; the
key is learned and all previously known
keys will no longer work with the
vehicle.
6. To learn a second key, turn the ignition off, insert the second key to be learned,
and turn the ignition on. After two keys are learned, the remaining
keys can be learned by following the
procedure in
“Programming with Two
Recognized Keys.”
The key has a bar-coded key tag that the
dealer or qualified locksmith can use to
make new keys. Store this information in a
safe place, not in the vehicle.
See your dealer if a replacement key or
additional key is needed.
If it becomes difficult to turn a key, inspect
the key blade for debris. Periodically clean
with a brush or pick.
If locked out of the vehicle, see Roadside
Assistance Program 0431.
With an active OnStar or connected service
plan, an OnStar Advisor may remotely
unlock the vehicle. See OnStar Overview
0 440.
Keys (Keyless Access)
{Warning
Leaving children in a vehicle with an
ignition key or Remote Keyless Entry
(RKE) transmitter is dangerous and
(Continued)

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
10 Keys, Doors, and Windows
Warning (Continued)
children or others could be seriously
injured or killed. They could operate the
power window or other controls or make
the vehicle move. The windows will
function with the key in the ignition or
with the RKE transmitter in the vehicle,
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 or an RKE transmitter.
If the vehicle has the Keyless Access system,
the transmitter has a button on the side of
the transmitter used to remove the key.This key is used for the driver door and
glove box.
Press the button to remove the key. Never
pull the key out without pressing the
button.
See your dealer if a replacement key or
additional key is needed.
If it becomes difficult to turn a key, inspect
the key blade for debris. Periodically clean
with a brush or pick.
With an active OnStar or connected service
plan, an OnStar Advisor may remotely
unlock the vehicle. See
OnStar Overview
0 440. If locked out of the vehicle, see
Roadside
Assistance Program 0431.
If equipped with memory seats, RKE
transmitters 1 and 2 are linked to seating
positions of memory 1 or 2. See Memory
Seats 049.
Remote Keyless Entry (RKE)
System
See Radio Frequency Statement 0436.
If there is a decrease in the Remote Keyless
Entry (RKE) operating range:
.Check the distance. The transmitter may
be too far from the vehicle.
.Check the location. Other vehicles or
objects may be blocking the signal.
.Check the transmitter's battery. See
“Battery Replacement” later in this
section.
.If the transmitter is still not working
correctly, see your dealer or a qualified
technician for service.
Remote Keyless Entry (RKE)
System Operation (Key Access)
The RKE transmitter functions may work up
to 60 m (197 ft) away from 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 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
12 Keys, Doors, and Windows
Battery Replacement
{Warning
Never allow children to play with the RKE
transmitter. The transmitter contains a
small battery, which can be a choking
hazard. If swallowed, internal burns can
occur, resulting in severe injury or death.
Seek medical attention immediately if a
battery is swallowed.
{Warning
To avoid personal injury, do not touch
metal surfaces on the RKE transmitter
when it has been exposed to extreme
heat. These surfaces can be hot to the
touch at temperatures above 59 °C
(138 °F).
Caution
When replacing the battery, do not touch
any of the circuitry on the transmitter.
Static from your body could damage the
transmitter.
Caution
Always replace the battery with the
correct type. Replacing the battery with
an incorrect type could potentially create
a risk of battery explosion. Dispose of
used batteries according to instructions
and local laws. Do not attempt to burn,
crush, or cut the used battery, and avoid
exposing the battery to environments
with extremely low air pressures or high
temperatures.
Replace the battery in the transmitter soon
if the REPLACE BATTERY IN REMOTE KEY
displays in the Driver Information
Center (DIC). To replace the battery:
1. Separate and remove the back cover of
the transmitter with a flat, thin object,
such as a coin.