
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
14 Keys, Doors, and Windows
Keys, Doors, and
Windows
Keys and Locks
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Remote Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Remote Key Operation . . . . . . . . . . . . . . . . . . 15
Remote Vehicle Start . . . . . . . . . . . . . . . . . . . 21
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Power Door Locks . . . . . . . . . . . . . . . . . . . . . . . 23
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 23
Automatic Door Locks . . . . . . . . . . . . . . . . . . 23
Lockout Protection . . . . . . . . . . . . . . . . . . . . . . 23
Safety Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Doors
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Transporting Items That CanCatch Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Power Assist Steps . . . . . . . . . . . . . . . . . . . . . . 31
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . . . . . . . . . 32
Vehicle Alarm System . . . . . . . . . . . . . . . . . . 32
Steering Column Lock . . . . . . . . . . . . . . . . . . . 33
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Immobilizer Operation . . . . . . . . . . . . . . . . . . 33
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 34
Manual Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 34
Trailer-Tow Mirrors . . . . . . . . . . . . . . . . . . . . . 35
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
Truck Bed Camera Rearview Mirror . . . . . 41
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Power Windows . . . . . . . . . . . . . . . . . . . . . . . . 42
Rear Windows . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Sun Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Keys and Locks
Keys
{Warning
Leaving children in a vehicle with a
remote 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 remote key 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 a remote key.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
22 Keys, Doors, and Windows
Press the brake pedal and turn the ignition
on to drive the vehicle.
Total Engine Run Time
Remote start can be used for up to
30 minutes of total engine run time.
After two remote starts of 15 minutes,
or multiple shorter time starts totaling
30 minutes have been used, the vehicle
must be started and then turned off before
the remote start can be used again.
Canceling a Remote Start
To cancel a remote start, do one of the
following:
.PressS. The parking lamps will turn off.
.Turn on the hazard warning flashers.
.Turn the ignition on and then off.
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(Continued)
Warning (Continued)
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 key.
.Use Keyless Access, if equipped.
.Use the key in the driver door or the
passenger door, if equipped. From inside, pull the door handle once to
unlock the door. Pull the handle again to
open the door.
See
Vehicle Alarm System 032.
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 Key Operation 015.
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 cylinder

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
24 Keys, Doors, and Windows
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 key.
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.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
48 Seats and Restraints
If you are installing a child restraint in the
rear seat, seeLower Anchors and Tethers for
Children (LATCH System) 081.
Center Headrest
The vehicle’s rear seat may be equipped
with a headrest in the center seating
position that cannot be adjusted.
If you are installing a child restraint in the
rear seat, see Lower Anchors and Tethers for
Children (LATCH System) 081.
Front Seats
Seat Adjustment
{Warning
You can lose control of the vehicle if you
try to adjust a driver seat while the
vehicle is moving. Adjust the driver seat
only when the vehicle is not moving.
To adjust a manual seat:
1. Pull the handle at the front of the seat.
2. Slide the seat to the desired position and release the handle.
3. Try to move the seat back and forth to be sure it is locked in place.
To adjust the seatback, see Reclining
Seatbacks 049.
To adjust the lumbar support, if equipped,
see Lumbar Adjustment 050.
Center Seat
If equipped, the center front seatback
doubles as an armrest and cupholder/
storage area for the driver and passenger
when the center front seat is not used.
Pull the strap on the side of the center
seatback to fold the center seatback. Do not
use the center seatback as a seating position
when the seatback is folded down.
To raise the seatback, push the seatback
rearward until it locks in the upright
position. Push and pull on the seatback to
make sure it is locked.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 61
2. Pick up the latch plate and pull the beltacross 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 78. 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 position on the seat, move the seat
rearward or recline the seat until the
shoulder belt retractor lock releases.
Engaging the child restraint locking
feature in the front outboard seating
position may affect the passenger
sensing system, if equipped. See
Passenger Sensing System
069.
If the webbing locks in the latch plate
before it reaches the buckle, tilt the latch
plate flat to unlock.
3. Push the latch plate into the buckle until
it clicks.
Pull up on the latch plate to make sure
it is secure. If the belt is not long
enough, see Seat Belt Extender 063.
Position the release pushbutton on the
buckle so that the seat belt could be
quickly unbuckled if necessary.
If equipped with a shoulder belt height
adjuster, move it to the height that is
right for you. See "Shoulder Belt Height
Adjuster" later in this section for
instructions on use and important safety
information.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
76 Seats and Restraints
{Warning
Never allow a child to wear the seat belt
shoulder belt under both arms or behind
their back. A child can be seriously
injured by not wearing the lap-shoulder
belt properly. In a crash, the child would
not be restrained by the shoulder belt.
The child could move too far forward
increasing the chance of head and neck
injury. The child might also slide under
the lap belt. The belt force would then be
applied right on the abdomen. That could
cause serious or fatal injuries. The
shoulder belt should go over the shoulder
and across the chest.
Infants and Young Children
Everyone in a vehicle needs protection! This
includes infants and all other children.
Neither the distance traveled nor the age
and size of the traveler changes the need,
for everyone, to use safety restraints. In
fact, the law in every state in the United
States and in every Canadian province says
children up to some age must be restrained
while in a vehicle.
{Warning
Children can be seriously injured or killed
if the shoulder belt is worn behind their
back, under their legs, or wrapped around(Continued)
Warning (Continued)
their 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 the
child. Never leave children unattended in
a vehicle and never allow children to
improperly wear, or play with, the seat
belts.
Every time infants and young children ride
in vehicles, they should have the protection
provided by appropriate child restraints.
Neither the vehicle seat belt system nor its
airbag system is designed for them.
Children who are not restrained properly can
strike other people, or can be thrown out of
the vehicle.
{Warning
Never hold an infant or a child while
riding in a vehicle. Due to crash forces, an
infant or a child will become so heavy it (Continued)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
86 Seats and Restraints
According to accident statistics, children and
infants are safer when properly restrained in
a child restraint system or infant restraint
system secured in a rear seating position.
SeeWhere to Put the Restraint 080 for
additional information.
Securing a Child Restraint Designed for
the LATCH System
{Warning
A child could be seriously injured or killed
in a crash if the child restraint is not
properly attached to the vehicle using
either the LATCH anchors or the vehicle
seat belt. Follow the instructions that
came with the child restraint and the
instructions in this manual.
{Warning
Do not attach more than one child
restraint to a single anchor, except for
the center top tether anchors in the crew
cab models. Attaching more than one
child restraint to a single anchor could
cause the anchor or attachment to come
loose or even break during a crash.
(Continued)
Warning (Continued)
A child or others could be injured. To
reduce the risk of serious or fatal injuries
during a crash, attach only one child
restraint per anchor.
{Warning
Children can be seriously injured or
strangled if a shoulder belt is wrapped
around their 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 a child’s neck. If the
shoulder belt is locked and tightened
around a child’s neck, the only way to
loosen the belt is to cut it.
Buckle any unused seat belts behind the
child restraint so children cannot reach
them. Pull the shoulder belt all the way
out of the retractor to set the lock, and(Continued)
Warning (Continued)
tighten the belt behind the child restraint
after the child restraint has been
installed.
Caution
Do not let the LATCH attachments rub
against the vehicle’s seat belts. This may
damage these parts. If necessary, move
buckled seat belts to avoid rubbing the
LATCH attachments.
Do not fold the rear seat cushion when
the seat is occupied. Do not fold the
empty rear seat with a seat belt buckled.
This could damage the seat belt or the
seat. Unbuckle and return the seat belt to
its stowed position, before folding
the seat.
If you need to secure more than one child
restraint in the rear seat, see Where to Put
the Restraint 080.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Index 427
Canadian Vehicle Owners . . . . . . . . . . . . . . . . . . .2
Capacities and Specifications . . . . . . . . . . . . . 402
Carbon MonoxideEngine Exhaust . . . . . . . . . . . . . . . . . . . . . . . . 222
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Winter Driving . . . . . . . . . . . . . . . . . . . . . . . . . 207
Cargo
Tie-Downs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Caution, Danger, and Warning . . . . . . . . . . . . . .2
Center High-Mounted Stoplamp (CHMSL)
and Cargo Lamp . . . . . . . . . . . . . . . . . . . . . 335
Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Center Console Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Chains, Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
Charging
System Light . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Wireless . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Check Engine Light (Malfunction Indicator) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Child Restraints Infants and Young Children . . . . . . . . . . . . . 76
Lower Anchors and Tethers forChildren . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Older Children . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Securing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92, 95
Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Child Safety Locks . . . . . . . . . . . . . . . . . . . . . . . . 24
Circuit Breakers . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Cleaning
Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
Climate Control Systems . . . . . . . . . . . . . . . . . . 191 Air Conditioning . . . . . . . . . . . . . . . . . . . . . . . . 191
Dual Automatic . . . . . . . . . . . . . . . . . . . . . . . . 193
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Cluster, Instrument . . . . . . . . . . . . . . . . . . . 112, 113
Collision Alert Forward (FCA) System . . . . . . . . . . . . . . . . . 263
Collision Damage Repair . . . . . . . . . . . . . . . . . . 411
Compartments Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Compass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Connected Services Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
Connections Connected Services . . . . . . . . . . . . . . . . . . . . 422
Control Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
Traction and Electronic Stability . . . . . . . 236
Control Light Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Control of a Vehicle . . . . . . . . . . . . . . . . . . . . . 200
Controls
Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . 156
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Coolant Engine Temperature Gauge . . . . . . . . . . . . . 118
Engine Temperature Warning Light . . . . 128
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191, 193
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Courtesy Transportation Program . . . . . . . . 410
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Adaptive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Cupholders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Customer Assistance Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
Text Telephone (TTY) Users . . . . . . . . . . . . 407
Customer Information Publications Ordering Information . . . . . 413
Customer Satisfaction Procedure . . . . . . . . . 405
Cybersecurity . . . . . . . . . . . . . . . . . . . . . . . . . . . . .415
D
Damage Repair, Collision . . . . . . . . . . . . . . . . . . 411
Danger, Warning, and Caution . . . . . . . . . . . . . .2
Dashboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Data Collection Infotainment System . . . . . . . . . . . . . . . . . . 416