adjust GMC SIERRA 2021 User Guide

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Seats and Restraints 49
To adjust a manual seatback:1. Lift the lever. The seatback will automatically fold
forward.
2. To recline, move the seatback rearward to the desired position, then release the
lever to lock the seatback in place.
3. Push and pull on the seatback to make sure it is locked.
To return the seatback to the upright
position: 1. Lift the lever fully without applying pressure to the seatback, and the
seatback will return to the upright
position. 2. Push and pull on the seatback to make
sure it is locked.
Power Reclining Seatbacks
To recline a power seatback, if equipped:
.Tilt the top of the control rearward to
recline.
.Tilt the top of the control forward to
raise.
Memory Seats
If equipped, memory seats allow two drivers
to save and recall their unique seat positions
for driving the vehicle, and a shared exit
position for getting out of the vehicle. Other
feature positions may also be saved, such as
power mirrors, if equipped. Memory
positions are linked to RKE transmitter 1 or 2
for automatic memory recalls.
Before saving, adjust all available memory
feature positions. Turn the vehicle on and
then press and release SET; a beep will
sound. Then immediately press and hold 1,
2, or
B(Exit) until two beeps sound. To
manually recall these positions, press and

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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50 Seats and Restraints
hold 1, 2, orBuntil the saved position is
reached. Follow the instructions under
“Saving Memory Positions.”
The vehicle identifies the current driver’s RKE
transmitter number (1–8). See Remote
Keyless Entry (RKE) System Operation (Key
Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013. Only RKE
transmitters 1 and 2 can be used for
automatic memory recalls. A Driver
Information Center (DIC) welcome message
indicating the transmitter number may
display for the first few ignition cycles
following a transmitter change. For Seat
Entry Memory to work properly, save the
positions to the memory button (1 or 2)
matching the RKE transmitter number
displayed in the DIC welcome message.
Carry the linked RKE transmitter when
entering the vehicle.
Vehicle Personalization Settings
.To have the Seat Entry Memory
movement begin when the vehicle is
started, select the Settings menu, then
Vehicle, then Seating Position, and then
Seat Entry Memory. Select On or Off. See
“Seat Entry Memory” later in this section.
.To begin Seat Exit Memory movement
when the vehicle is turned off and the
driver door is opened, or when the vehicle
is turned off with the driver door already
opened, select the Settings menu, then
Vehicle, then Seating Position, and then
Seat Exit Memory. Select On or Off. See
“Seat Exit Memory”later in this section.
.SeeVehicle Personalization 0131 for
additional setting information.
Identifying Driver Number
To identify the driver number: 1. Move your RKE transmitter away from the vehicle.
2. Start the vehicle with another key or RKE transmitter. The DIC should display the
driver number for the other RKE
transmitter. Turn the vehicle off and
remove the key or RKE transmitter from
the vehicle.
3. Start the vehicle with the initial key or RKE transmitter. The DIC should display
the driver number of your RKE
transmitter.
Saving Memory Positions
Read these instructions completely before
saving memory positions. To save preferred driving positions 1 and 2:
1. Turn the vehicle on or to ACC/ ACCESSORY.
A DIC welcome message may indicate
driver number 1 or 2.
2. Adjust all available memory features to the desired driving position.
3. Press and release SET; a beep will sound.
4. Immediately press and hold the 1 or 2 memory button matching the above
DIC welcome message until two beeps
sound.
If too much time passes between
releasing SET and pressing 1, the
memory position will not be saved and
two beeps will not sound. Repeat
Steps 3 and 4.
1 or 2 corresponds to the driver number.
See “Identifying Driver Number”
previously in this section.
5. Repeat Steps 1–4 for a second driver using 1 or 2. RKE transmitters 3–8 will
not save memory positions.
To save the position for
Band Seat Exit
Memory features, repeat Steps 1–4 using
B. This saves the position for getting out
of the vehicle.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Seats and Restraints 57
Always use the correct buckle for your
seating position.
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 be able to
provide adequate protection. Never allow
seat belts to be routed under plastic trim
pieces.
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 74. 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

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But if a seat belt is not long enough, your
dealer will order you an extender. When
you go in to order it, take the heaviest coat
you will wear, so the extender will be long
enough for you. To help avoid personal
injury, do not let someone else use it, and
use it only for the seat it is made to fit. The
extender has been designed for adults.
Never use it for securing child restraints. For
more information on the proper use and fit
of seat belt extenders see the instruction
sheet that comes with the extender.
Safety System Check
Periodically check the seat belt reminder,
seat belts, buckles, latch plates, retractors,
shoulder belt height adjusters (if equipped),
and seat belt anchorages to make sure they
are all in working order. Look for any other
loose or damaged seat belt system parts
that might keep a seat belt system from
performing properly. See your dealer to
have it repaired. Torn, frayed, or twisted
seat belts may not protect you in a crash.
Torn or frayed seat belts can rip apart under
impact forces. If a belt is torn or frayed,
have it replaced immediately. If a belt is
twisted, it may be possible to untwist byreversing the latch plate on the webbing.
If the twist cannot be corrected, ask your
dealer to fix it.
Make sure the seat belt reminder light is
working. See
Seat Belt Reminders 0113.
Keep seat belts clean and dry. See Seat Belt
Care 060.
Seat Belt Care
Keep belts clean and dry.
Seat belts should be properly cared for and
maintained.
Seat belt hardware should be kept dry and
free of dust or debris. As necessary, exterior
hard surfaces and seat belt webbing may be
lightly cleaned with mild soap and water.
Ensure there is not excessive dust or debris
in the mechanism. If dust or debris exists in
the system please see the dealer. Parts may
need to be replaced to ensure proper
functionality of the system.
{Warning
Do not bleach or dye seat belt webbing.
It may severely weaken the webbing. In
a crash, they might not be able to
(Continued)
Warning (Continued)
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.

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64 Seats and Restraints
Frontal airbags are designed to inflate in
moderate to severe frontal or near frontal
crashes to help reduce the potential for
severe injuries, mainly to the driver's or
front outboard passenger's head and chest.
Whether the frontal airbags will or should
inflate is not based primarily on how fast
the vehicle is traveling. It depends on what
is hit, the direction of the impact, and how
quickly the vehicle slows down.
Frontal airbags may inflate at different crash
speeds depending on whether the vehicle
hits an object straight on or at an angle,
and whether the object is fixed or moving,
rigid or deformable, narrow or wide.
Frontal airbags are not intended to inflate
during vehicle rollovers, rear impacts,
or many side impacts.
In addition, the vehicle has advanced
technology frontal airbags. Advanced
technology frontal airbags adjust the
restraint according to crash severity.
Seat-mounted side impact airbags are
designed to inflate in moderate to severe
side crashes depending on the location of
the impact. Seat-mounted side impact
airbags are not designed to inflate in frontal
impacts, near frontal impacts, rollovers,or rear impacts. A seat-mounted side impact
airbag is designed to inflate on the side of
the vehicle that is struck.
Roof-rail airbags are designed to inflate in
moderate to severe side crashes depending
on the location of the impact. In addition,
these roof-rail airbags are designed to inflate
during a rollover or in a severe frontal
impact. Roof-rail airbags are not designed to
inflate in rear impacts. Both roof-rail airbags
will inflate when either side of the vehicle is
struck or if the sensing system predicts that
the vehicle is about to roll over on its side,
or in a severe frontal impact.
In any particular crash, no one can say
whether an airbag should have inflated
simply because of the vehicle damage or
repair costs.
What Makes an Airbag Inflate?
In a deployment event, the sensing system
sends an electrical signal triggering a release
of gas from the inflator. Gas from the
inflator fills the airbag causing the bag to
break out of the cover. The inflator, the
airbag, and related hardware are all part of
the airbag module.
For airbag locations, see
Where Are the
Airbags? 062.
How Does an Airbag Restrain?
In moderate to severe frontal or near frontal
collisions, even belted occupants can contact
the steering wheel or the instrument panel.
In moderate to severe side collisions, even
belted occupants can contact the inside of
the vehicle.
Airbags supplement the protection provided
by seat belts by distributing the force of the
impact more evenly over the
occupant's body.
Rollover capable roof-rail airbags are
designed to help contain the head and chest
of occupants in the outboard seating
positions in the first and second rows. The
rollover capable roof-rail airbags are
designed to help reduce the risk of full or
partial ejection in rollover events, although
no system can prevent all such ejections.
But airbags would not help in many types
of collisions, primarily because the
occupant's motion is not toward those
airbags. See When Should an Airbag Inflate?
0 63.
Airbags should never be regarded as
anything more than a supplement to seat
belts.

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68 Seats and Restraints
4. Reinstall the child restraint following thedirections provided by the child restraint
manufacturer and refer to Securing Child
Restraints (With the Seat Belt in the
Center Front Seat) 092 or
Securing Child Restraints (With the Seat
Belt in the Rear Seat) 088 or
Securing Child Restraints (With the Seat
Belt in the Front Passenger Seat) 092.
Make sure the seat belt retractor is
locked by pulling the shoulder belt all
the way out of the retractor when
installing the child restraint, even if the
child restraint is equipped with a seat
belt lock off. When the retractor lock is
set, the belt can be tightened but not
pulled out of the retractor.
5. If, after reinstalling the child restraint and restarting the vehicle, the ON
indicator is still lit, turn the vehicle off.
Then slightly recline the vehicle seatback
and adjust the seat cushion,
if adjustable, to make sure that the
vehicle seatback is not pushing the child
restraint into the seat cushion.
Also make sure the child restraint is not
trapped under the vehicle head restraint.
If this happens, adjust the head restraint.
See Head Restraints 045. 6. Restart the vehicle.
The passenger sensing system may or may
not turn off the airbag for a child in a child
restraint depending upon the child’s size.
It is better to secure child restraints in the
rear seat. Consider using another vehicle to
transport the child when a rear seat is not
available. Never put a rear-facing child
restraint in the front seat, even if the ON
indicator is not lit.
If the Off Indicator Is Lit for an
Adult-Sized Occupant
If a person of adult size is sitting in the
front outboard passenger seat, but the OFF
indicator is lit, it could be because that
person is not sitting properly in the seat or that the child restraint locking feature is
engaged. Use the following steps to allow
the system to detect that person and enable
the front outboard passenger frontal airbag:
1. Turn the vehicle off.
2. Remove any additional material from the seat, such as blankets, cushions, seat
covers, seat heaters, or seat massagers.
3. Place the seatback in the fully upright position.
4. Have the person sit upright in the seat, centered on the seat cushion, with legs
comfortably extended.
5. If the shoulder portion of the belt is pulled out all the way, the child restraint
locking feature will be engaged. This
may unintentionally cause the passenger
sensing system to turn the airbag off for
some adult-sized occupants. If this
happens, unbuckle the belt, let the belt
go back all the way, and then buckle the
belt again without pulling the belt out
all the way.
6. Restart the vehicle and have the person remain in this position for two to
three minutes after the ON indicator
is lit.

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Seats and Restraints 77
{Warning
A child in a child restraint in the center
front seat can be badly injured or killed
by the frontal airbags if they inflate.
Never secure a child restraint in the
center front seat. It is always better to
secure a child restraint in a rear seat.
Do not use child restraints in the center
front seat position.
If the vehicle does not have a rear seat that
will accommodate a rear-facing child
restraint, a rear-facing child restraint should
not be installed in the vehicle, even if the
airbag is off.
When securing a child restraint with the
seat belts in a rear seat position, study the
instructions that came with the child
restraint to make sure it is compatible with
this vehicle.
Child restraints and booster seats vary
considerably in size, and some may fit in
certain seating positions better than others.
Do not install a child restraint in any rear
seating position where it cannot be installed
securely. Depending on where you place the child
restraint and the size of the child restraint,
you may not be able to access adjacent seat
belts or LATCH anchors for additional
passengers or child restraints. Adjacent
seating positions should not be used if the
child restraint prevents access to or
interferes with the routing of the seat belt.
The seat in front of an installed child
restraint should be adjusted to ensure
proper installation according to the child
restraint manual.
Wherever a child restraint is installed, be
sure to follow the instructions that came
with the child restraint and secure the child
restraint properly.
Keep in mind that an unsecured child
restraint can move around in a collision or
sudden stop and injure people in the vehicle.
Be sure to properly secure any child
restraint in the vehicle
—even when no
child is in it.
Lower Anchors and Tethers for
Children (LATCH System)
The LATCH system secures a child restraint
during driving or in a crash. LATCH
attachments on the child restraint are used
to attach the child restraint to the anchors
in the vehicle. This system is designed to
make installation of a child restraint easier.
In order to use the LATCH system in your
vehicle, you need a child restraint that has
LATCH attachments. LATCH-compatible
rear-facing and forward-facing child seats can
be properly installed using either the LATCH
anchors or the vehicle’s seat belts. Do not
use both the seat belts and the LATCH
anchorage system to secure a rear-facing or
forward-facing child seat.
Booster seats use the vehicle’s seat belts to
secure the child and the booster seat. If the
manufacturer recommends that the booster
seat be secured with the LATCH system, this
can be done as long as the booster seat can
be positioned properly and there is no
interference with the proper positioning of
the lap-shoulder belt on the child.

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84 Seats and Restraints
Regular Cab Models1. For models without a rear seat, forward-facing child restraints should
only be installed in the right front
seating position with belts and a top
tether. See Securing Child Restraints
(With the Seat Belt in the Center Front
Seat) 092 or
Securing Child Restraints (With the Seat
Belt in the Rear Seat) 088 or
Securing Child Restraints (With the Seat
Belt in the Front Passenger Seat) 092.
If the child restraint manufacturer
recommends that the top tether be
attached, attach and tighten the top
tether to the top tether anchor, if your
vehicle has one. Refer to the child
restraint instructions and the following
steps:
1.1. Find the top tether anchor.
1.2. Route, attach, and tighten the top tether according to your child
restraint instructions and the
following instructions:
If the position you are using has an
adjustable head restraint and you
are using a dual tether, route the
tether around the head restraint.
If the position you are using has an
adjustable head restraint and you
are using a single tether, raise the
head restraint and route the tether
under the head restraint and in
between the head restraint posts. 2. Make sure the child restraint top tether
hook is completely closed and secured to
the top tether anchor.
3. Secure the child restraint in the right front seating position with the vehicle
belts. See Securing Child Restraints (With
the Seat Belt in the Center Front Seat)
0 92 or
Securing Child Restraints (With the Seat
Belt in the Rear Seat) 088 or
Securing Child Restraints (With the Seat
Belt in the Front Passenger Seat) 092.
4. Before placing a child in the child restraint, make sure it is securely held in
place. To check, grasp the child restraint
at the belt path and attempt to move it
side to side and back and forth. There
should be no more than 2.5 cm (1 in) of
movement for proper installation.
Double and Crew Cab Models 1. Attach and tighten the lower attachments to the lower anchors. If the
child restraint does not have lower
attachments or the desired seating
position does not have lower anchors,
secure the child restraint with the top
tether and the seat belt. Refer to the
child restraint manufacturer instructions
and the instructions in this manual.

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88 Seats and 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.
To reinstall the head restraint or headrest:
1. Insert the head restraint or headrest posts into the holes in the top of the
seatback. The notches on the posts must
face the driver side of the vehicle. 2. Push the head restraint or
headrest down.
3. Try to move the head restraint or headrest to make sure that it is locked in
place.
Replacing LATCH System Parts
After a Crash
{Warning
A crash can damage the LATCH system in
the vehicle. A damaged LATCH system
may not properly secure the child
restraint, resulting in serious injury or
even death in a crash. To help make sure
the LATCH system is working properly
after a crash, see your dealer to have the
system inspected and any necessary
replacements made as soon as possible.
If the vehicle has the LATCH system and it
was being used during a crash, new LATCH
system parts may be needed.
New parts and repairs may be necessary
even if the LATCH system was not being
used at the time of the crash.
Securing Child Restraints (With
the Seat Belt in the Rear Seat)
When securing a child restraint with the
seat belts in a rear seat position, study the
instructions that came with the child
restraint to make sure it is compatible with
this vehicle.
If the child restraint has the LATCH system,
see Lower Anchors and Tethers for Children
(LATCH System) 077 for how and where to
install the child restraint using LATCH. If a
child restraint is secured in the vehicle using
a seat belt and it uses a top tether, see
Lower Anchors and Tethers for Children
(LATCH System) 077 for top tether anchor
locations.
Do not secure a child seat in a position
without a top tether anchor if a national or
local law requires that the top tether be
anchored, or if the instructions that come
with the child restraint say that the top
tether must be anchored.
In Canada, the law requires that
forward-facing child restraints have a top
tether, and that the tether be attached.

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Seats and Restraints 93
Do not secure a child seat in a position
without a top tether anchor if a national or
local law requires that the top tether be
anchored, or if the instructions that come
with the child restraint say that the top
tether must be anchored.
In Canada, the law requires that
forward-facing child restraints have a top
tether, and that the tether be attached.
When using the lap-shoulder belt to secure
the child restraint in this position, follow the
instructions that came with the child
restraint and the following instructions:1. Move the seat as far back as it will go before securing the forward-facing child
restraint. Move the seat upward or the
seatback to an upright position,
if needed, to get a tight installation of
the child restraint.
When the passenger sensing system has
turned off the front outboard passenger
frontal airbag, the OFF indicator on the
passenger airbag status indicator should
light and stay lit when you start the
vehicle. See Passenger Airbag Status
Indicator 0114. 2. Put the child restraint on the seat.
3. Pick up the latch plate, and run the lap
and shoulder portions of the vehicle seat
belt through or around the child
restraint. The child restraint instructions
will show you how.
Tilt the latch plate to adjust the belt if
needed.
4. Push the latch plate into the buckle untilit clicks.
Position the release button on the
buckle, away from the child restraint, so
that the seat belt could be quickly
unbuckled if necessary.