GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Introduction 3
A circle with a slash through it is a safety
symbol which means“Do not,” “Do not do
this,” or“Do not let this happen.”
Symbols
The vehicle has components and labels that
use symbols instead of text. Symbols are
shown along with the text describing the
operation or information relating to a
specific component, control, message, gauge,
or indicator.
M:Shown when the owner’s manual has
additional instructions or information.
*: Shown when the service manual has
additional instructions or information.
0: Shown when there is more information
on another page — “see page.” Vehicle Symbol Chart
Here are some additional symbols that may
be found on the vehicle and what they
mean. See the features in this manual for
information.
u:
Air Conditioning System
G:Air Conditioning Refrigerant Oil
9:Airbag Readiness Light
!:Antilock Brake System (ABS)
$:Brake System Warning Light
9:Dispose of Used Components Properly
P:Do Not Apply High Pressure Water
B:Engine Coolant Temperature
_:Flame/Fire Prohibited
H: Flammable
[:Forward Collision Alert
R:Fuse Block Cover Lock Location
+:Fuses
j:ISOFIX/LATCH System Child Restraints
Q:Keep Fuse Block Covers Properly
Installed
|: Lane Change Alert
@:Lane Departure Warning
A:Lane Keep Assist
*: Malfunction Indicator Lamp
::Oil Pressure
X:Park Assist
~:Pedestrian Ahead Indicator
O:Power
7:Rear Cross Traffic Alert
I:Registered Technician
/:Remote Vehicle Start
h:Risk of Electrical Fire
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Keys, Doors, and Windows 9
{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 053.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Seats and Restraints 49
Seats and Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . 49
Front Seats
Seat Adjustment . . . . . . . . . . . . . . . . . . . . . . . 50
Center Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Power Seat Adjustment . . . . . . . . . . . . . . . . . 51
Reclining Seatbacks . . . . . . . . . . . . . . . . . . . . . 52
Lumbar Adjustment . . . . . . . . . . . . . . . . . . . . . 53
Memory Seats . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Heated and Ventilated Front Seats . . . . . 56
Rear Seats
Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Heated Rear Seats . . . . . . . . . . . . . . . . . . . . . . 58
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
How to Wear Seat Belts Properly . . . . . . 59
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . . . . 61
Seat Belt Use During Pregnancy . . . . . . . . 64
Seat Belt Extender . . . . . . . . . . . . . . . . . . . . . 64
Safety System Check . . . . . . . . . . . . . . . . . . . 64
Seat Belt Care . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Replacing Seat Belt System Parts after aCrash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Airbag System
Airbag System . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Where Are the Airbags? . . . . . . . . . . . . . . . . 67
When Should an Airbag Inflate? . . . . . . . . 68
What Makes an Airbag Inflate? . . . . . . . . 68
How Does an Airbag Restrain? . . . . . . . . . 69
What Will You See after an Airbag
Inflates? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Passenger Sensing System . . . . . . . . . . . . . 70
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Adding Equipment to the Airbag-Equipped Vehicle . . . . . . . . . . . . . . 74
Airbag System Check . . . . . . . . . . . . . . . . . . . 75
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Child Restraints
Older Children . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Infants and Young Children . . . . . . . . . . . . . 77
Child Restraint Systems . . . . . . . . . . . . . . . . 79
Where to Put the Restraint . . . . . . . . . . . . 80
Lower Anchors and Tethers for Children(LATCH System) . . . . . . . . . . . . . . . . . . . . . . . 82
Replacing LATCH System Parts After a Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Securing Child Restraints (With the Seat Belt in the Rear Seat) . . . . . . . . . . . . . . . . . 92
Securing Child Restraints (With the Seat Belt in the Front Passenger Seat) . . . . . 96
Securing Child Restraints (With the Seat Belt in the Center Front Seat) . . . . . . . . 99
Head Restraints
{
Warning
With head restraints that are not
installed and adjusted properly, there is a
greater chance that occupants will suffer
a neck/spinal injury in a crash. Do not
drive until the head restraints for all
occupants are installed and adjusted
properly.
Front Seats
The vehicle's front seats have adjustable
head restraints in the outboard seating
positions.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Seats and Restraints 59
When riding in a vehicle, you travel as fast
as the vehicle does. If the vehicle stops
suddenly, you keep going until something
stops you. It could be the windshield, the
instrument panel, or the seat belts!
When you wear a seat belt, you and the
vehicle slow down together. There is more
time to stop because you stop over a longer
distance and, when worn properly, your
strongest bones take the forces from the
seat belts. That is why wearing seat belts
makes such good sense.
Questions and Answers About Seat Belts
Q: Will I be trapped in the vehicle after acrash if I am wearing a seat belt?
A: You could be— whether you are
wearing a seat belt or not. Your chance
of being conscious during and after a
crash, so you canunbuckle and get out,
is much greater if you are belted.
Q: If my vehicle has airbags, why should I have to wear seat belts?
A: Airbags are supplemental systems only.
They work withseat belts —not instead
of them. Whether or not an airbag is
provided, all occupants still have to
buckle up to get the most protection. Also, in nearly all states and in all
Canadian provinces, the law requires
wearing seat belts.
How to Wear Seat Belts Properly
Follow these rules for everyone's protection.
There are additional things to know about
seat belts and children, including smaller
children and infants. If a child will be riding
in the vehicle, see
Older Children075 or
Infants and Young Children 077. Review and
follow the rules for children in addition to
the following rules.
It is very important for all occupants to
buckle up. Statistics show that unbelted
people are hurt more often in crashes than
those who are wearing seat belts.
There are important things to know about
wearing a seat belt properly.
.Sit up straight and always keep your feet
on the floor in front of you (if possible).
.Wear the lap part of the belt low and
snug on the hips, just touching the
thighs. In a crash, this applies force to the
strong pelvic bones and you would be
less likely to slide under the lap belt.
If you slid under it, the belt would apply
force on your abdomen. This could cause
serious or even fatal injuries.
.Wear the shoulder belt over the shoulder
and across the chest. These parts of the
body are best able to take belt
restraining forces. The shoulder belt locks
if there is a sudden stop or crash.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Seats and Restraints 61
Never route the lap or shoulder belt over an
armrest.
{Warning
The seat belt can be pinched if it is
routed under plastic trim on the seat,
such as trim around the rear seatback
folding handle or side airbag. In a crash,
pinched seat belts might not provide
adequate protection. Never allow seat
belts to be routed under plastic trim
pieces.
{Warning
You can be seriously injured or killed if
the shoulder belt is worn behind your
back, under your legs, or wrapped around
your neck. The shoulder belt can tighten
but cannot be loosened if it is locked. The
shoulder belt locks when it is pulled all
the way out of the retractor. It unlocks
when the shoulder belt is allowed to go
all the way back into the retractor, but it
cannot do this if it is wrapped around
you. You may have to cut the seat belt if
it is locked and tightened around you.
Lap-Shoulder Belt
All seating positions in the vehicle have a
lap-shoulder belt.
The following instructions explain how to
wear a lap-shoulder belt properly.1. Adjust the seat, if the seat is adjustable, so you can sit up straight. To see how,
see “Seats” in the Index.
2. Pick up the latch plate and pull the belt
across you. Do not let it get twisted.
The lap-shoulder belt may lock if you
pull the belt across you very quickly.
If this happens, let the belt go back
slightly to unlock it. Then pull the belt
across you more slowly.
If the shoulder portion of a passenger
belt is pulled out all the way, the child
restraint locking feature may be
engaged. See Child Restraint Systems
0 79. If this occurs, let the belt go back
all the way and start again. If the
locking feature stays engaged after
letting the belt go back to stowed
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Seats and Restraints 65
{Warning
Do not bleach or dye seat belt webbing.
It may severely weaken the webbing. In
a crash, they might not be able to
provide adequate protection. Clean and
rinse seat belt webbing only with mild
soap and lukewarm water. Allow the
webbing to dry.
Replacing Seat Belt System Parts
after a Crash
{Warning
A crash can damage the seat belt system
in the vehicle. A damaged seat belt
system may not properly protect the
person using it, resulting in serious injury
or even death in a crash. To help make
sure the seat belt systems are working
properly after a crash, have them
inspected and any necessary
replacements made as soon as possible.
After a minor crash, replacement of seat
belts may not be necessary. But the seat
belt assemblies that were used during any crash may have been stressed or damaged.
See your dealer to have the seat belt
assemblies inspected or replaced.
New parts and repairs may be necessary
even if the seat belt system was not being
used at the time of the crash.
Have the seat belt pretensioners checked if
the vehicle has been in a crash, or if the
airbag readiness light stays on after you
start the vehicle or while you are driving.
See
Airbag Readiness Light 0119.
Airbag System
The vehicle has the following airbags:
.A frontal airbag for the driver
.A frontal airbag for the front outboard
passenger
.A seat-mounted side impact airbag for the
driver
.A seat-mounted side impact airbag for the
front outboard passenger
.A roof-rail airbag for the driver and the
passenger seated directly behind the
driver
.A roof-rail airbag for the front outboard
passenger and the passenger seated
directly behind the front outboard
passenger
All vehicle airbags have the word AIRBAG on
the trim or on a label near the deployment
opening.
For frontal airbags, the word AIRBAG is on
the center of the steering wheel for the
driver and on the instrument panel for the
front outboard passenger.
For seat-mounted side impact airbags, the
word AIRBAG is on the side of the seatback
or side of the seat closest to the door.
For roof-rail airbags, the word AIRBAG is on
the ceiling or trim.
Airbags are designed to supplement the
protection provided by seat belts. Even
though today's airbags are also designed to
help reduce the risk of injury from the force
of an inflating bag, all airbags must inflate
very quickly to do their job.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
66 Seats and Restraints
Here are the most important things to know
about the airbag system:
{Warning
You can be severely injured or killed in a
crash if you are not wearing your seat
belt, even with airbags. Airbags are
designed to work with seat belts, not
replace them. Also, airbags are not
designed to inflate in every crash. In
some crashes seat belts are the only
restraint. SeeWhen Should an Airbag
Inflate? 068.
Wearing your seat belt during a crash
helps reduce your chance of hitting
things inside the vehicle or being ejected
from it. Airbags are “supplemental
restraints” to the seat belts. Everyone in
the vehicle should wear a seat belt
properly, whether or not there is an
airbag for that person.
{Warning
Because airbags inflate with great force
and faster than the blink of an eye,
anyone who is up against, or very close
to, any airbag when it inflates can be
seriously injured or killed. Do not sit
unnecessarily close to any airbag, as you
would be if sitting on the edge of the
seat or leaning forward. Seat belts help
keep you in position before and during a
crash. Always wear a seat belt, even with
airbags. The driver should sit as far back
as possible while still maintaining control
of the vehicle. The seat belts and the
front outboard passenger airbags are
most effective when you are sitting well
back and upright in the seat with both
feet on the floor.
Occupants should not lean on or sleep
against the door or side windows in
seating positions with seat-mounted side
impact airbags and/or roof-rail airbags.
{Warning
Children who are up against, or very
close to, any airbag when it inflates can
be seriously injured or killed. Always
secure children properly in the vehicle. To
read how, see Older Children 075 or
Infants and Young Children 077.
There is an airbag readiness light on the
instrument cluster, which shows the airbag
symbol.
The system checks the airbag electrical
system for malfunctions. The light tells you
if there is an electrical problem. See Airbag
Readiness Light 0119.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Seats and Restraints 67
Where Are the Airbags?
The driver frontal airbag is in the center of
the steering wheel.
The front outboard passenger frontal airbag
is in the passenger side instrument panel.
Driver Side Shown, Passenger Side Similar
The driver and front outboard passenger
seat-mounted side impact airbags are in the
side of the seatbacks closest to the door.
Driver Side Crew Cab Shown, Passenger Side Double and Regular Cabs Similar
The roof-rail airbags for the driver, front
outboard passenger, and second row
outboard passengers are in the ceiling above
the side windows.
{Warning
If something is between an occupant and
an airbag, the airbag might not inflate
properly or it might force the object into
that person causing severe injury or even
death. The path of an inflating airbag
must be kept clear. Do not put anything
between an occupant and an airbag, and (Continued)