lock GMC YUKON XL 2018 Service Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Seats and Restraints 79
3. Push the latch plate into the
buckle until it clicks. If the latch
plate will not go fully into the
buckle, check if the correct
buckle is being used.
Pull up on the latch plate to
make sure it is secure. If the
belt is not long enough, see
Seat Belt Extender 0 83 .
Position the release button on
the buckle so that the seat belt
could be quickly unbuckled if
necessary.
4. If equipped with a shoulder belt
height adjuster, move it to the
height that is right for you. See
“ Shoulder Belt Height Adjuster ” in this section for instructions
on use and important safety
information.
5. To make the lap part tight, pull
up on the shoulder belt.
For third row seats, it may be
necessary to pull stitching on
the seat belt through the latch
plate to fully tighten the lap belt
on smaller occupants. To unlatch the belt, push the button
on the buckle. The belt should
return to its stowed position.
For third row seats, slide the latch
plate up the safety webbing when
the seat belt is not in use. The latch
plate should rest on the stitching on
the seat belt.
Always stow the seat belt slowly.
If the seat belt webbing returns
quickly to the stowed position, the
retractor may lock and cannot be
pulled out. If this happens, pull the
seat belt straight out firmly to unlock
the webbing, and then release it.
If the webbing is still locked in the
retractor, see your dealer.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
80 Seats and Restraints Before a door is closed, be sure the
seat belt is out of the way. If a door
is slammed against a seat belt,
damage can occur to both the seat
belt and the vehicle.
Shoulder Belt Height Adjuster The vehicle has a shoulder belt
height adjuster for the driver and
front outboard passenger positions.
Adjust the height so the shoulder
portion of the belt is on the shoulder
and not falling off of it. The belt
should be close to, but not
contacting, the neck. Improper
shoulder belt height adjustment
could reduce the effectiveness of
the seat belt in a crash. See How to
Wear Seat Belts Properly 0 77 . Push down on the release button to
move the height adjuster to the
desired position.
Move the adjuster up by pushing up
on the shoulder belt guide.
After the adjuster is set to the
desired position, try to move it down
without pushing the release button
to make sure it has locked into
position.
Seat Belt Pretensioners
This vehicle has seat belt
pretensioners for front outboard
occupants. Although the seat belt
pretensioners cannot be seen, they
are part of the seat belt assembly. They can help tighten the seat belts
during the early stages of a
moderate to severe frontal, near
frontal, or rear crash if the threshold
conditions for pretensioner
activation are met. Seat belt
pretensioners can also help tighten
the seat belts in a side crash or a
rollover event.
Pretensioners work only once. If the
pretensioners activate in a crash,
the pretensioners and probably
other parts of the vehicle's seat belt
system will need to be replaced.
See Replacing Seat Belt System
Parts after a Crash 0 84 .
Do not sit on the outboard seat belt
while entering or exiting the vehicle
or at any time while sitting in the
seat. Sitting on the seat belt can
damage the webbing and hardware.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
88 Seats and Restraints Warning (Continued)inflating airbag must be kept
clear. Do not put anything
between an occupant and an
airbag, and do not attach or put
anything on the steering wheel
hub or on or near any other
airbag covering.
Do not use seat or console
accessories that block the
inflation path of a seat-mounted
side impact airbag or the front
center airbag, if equipped.
Never secure anything to the roof
of a vehicle with roof-rail airbags
by routing a rope or tie-down
through any door or window
opening. If you do, the path of an
inflating roof-rail airbag will be
blocked.
When Should an Airbag
Inflate? This vehicle is equipped with
airbags. See Airbag System 0 85 .
Airbags are designed to inflate if the impact exceeds the specific airbag
system's deployment threshold.
Deployment thresholds are used to
predict how severe a crash is likely
to be in time for the airbags to
inflate and help restrain the
occupants. The vehicle has
electronic sensors that help the
airbag system determine the
severity of the impact. Deployment
thresholds can vary with specific
vehicle design.
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.
The vehicle also has a seat position
sensor that enables the sensing
system to monitor the position of the
driver seat. The seat position sensor
provides information that is used to
adjust the deployment of the driver
frontal airbag.
The front center airbag, if equipped,
is designed to inflate in moderate to
severe side crashes depending
upon the location of the impact,
when either side of the vehicle is
struck. In addition, the front center
airbag is designed to inflate when
the sensing system predicts that the
vehicle is about to roll over on its
side. The front center airbag is not

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
90 Seats and Restraints
What Will You See after
an Airbag Inflates? After frontal and seat-mounted side
impact airbags inflate, they quickly
deflate, so quickly that some people
may not even realize the airbags
inflated. The front center airbag and
roof-rail airbags may still be at least
partially inflated for some time after
they inflate. Some components of
the airbag module may be hot for
several minutes. For location of the
airbags, see Where Are the
Airbags? 0 86 .
The parts of the airbag that come
into contact with you may be warm,
but not too hot to touch. There may
be some smoke and dust coming
from the vents in the deflated
airbags. Airbag inflation does not
prevent the driver from seeing out of
the windshield or being able to steer
the vehicle, nor does it prevent
people from leaving the vehicle. { WarningWhen an airbag inflates, there
may be dust in the air. This dust
could cause breathing problems
for people with a history of
asthma or other breathing trouble.
To avoid this, everyone in the
vehicle should get out as soon as
it is safe to do so. If you have
breathing problems but cannot
get out of the vehicle after an
airbag inflates, then get fresh air
by opening a window or a door.
If you experience breathing
problems following an airbag
deployment, you should seek
medical attention.
The vehicle has a feature that may
automatically unlock the doors, turn
on the interior lamps and hazard
warning flashers, and shut off the
fuel system after the airbags inflate.
The feature may also activate,
without airbag inflation, after an
event that exceeds a predetermined
threshold. After turning the ignition
off and then on again, the fuel system will return to normal
operation; the doors can be locked,
the interior lamps can be turned off,
and the hazard warning flashers can
be turned off using the controls for
those features. If any of these
systems are damaged in the crash
they may not operate as normal.
{ WarningA crash severe enough to inflate
the airbags may have also
damaged important functions in
the vehicle, such as the fuel
system, brake and steering
systems, etc. Even if the vehicle
appears to be drivable after a
moderate crash, there may be
concealed damage that could
make it difficult to safely operate
the vehicle.
Use caution if you should attempt
to restart the engine after a crash
has occurred.
In many crashes severe enough to
inflate the airbag, windshields are
broken by vehicle deformation.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Seats and Restraints 93wear a seat belt properly — whether
or not there is an airbag for that
person.
{ WarningIf the airbag readiness light ever
comes on and stays on, it means
that something may be wrong
with the airbag system. To help
avoid injury to yourself or others,
have the vehicle serviced right
away. See Airbag Readiness
Light 0 141 for more information,
including important safety
information.
If the On Indicator Is Lit for a
Child Restraint The passenger sensing system is
designed to turn off the front
outboard passenger frontal airbag if
the system determines that an infant
is present in a child restraint. If a
child restraint has been installed
and the on indicator is lit:
1. Turn the vehicle off. 2. Remove the child restraint from
the vehicle.
3. Remove any additional items
from the seat such as blankets,
cushions, seat covers, seat
heaters, or seat massagers.
4. Reinstall the child restraint
following the directions
provided by the child restraint
manufacturer and refer to
Securing Child Restraints (With
the Seat Belt in the Center
Front Seat) 0 114 or Securing
Child Restraints (With the Seat
Belt in the Front Passenger
Seat) 0 114 or Securing Child
Restraints (With the Seat Belt
in the Rear Seat) 0 112 .
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
0 61 .
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 the child restraint in a rear
seat. Never put a rear-facing child
restraint in the front seat, even if the
on indicator is not lit.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
94 Seats and Restraints 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. { WarningIf the front outboard passenger
airbag is turned off for an
adult-sized occupant, the airbag
will not be able to inflate and help
protect that person in a crash,
resulting in an increased risk of
serious injury or even death. An
adult-sized occupant should not
ride in the front outboard
passenger seat, if the passenger
airbag off indicator is lit.
Additional Factors Affecting
System Operation Seat belts help keep the passenger
in position on the seat during
vehicle maneuvers and braking,
which helps the passenger sensing
system maintain the passenger
airbag status. See “ Seat Belts ” and
“ Child Restraints ” in the Index for
additional information about the
importance of proper restraint use.
A thick layer of additional material,
such as a blanket or cushion,
or aftermarket equipment such as

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Seats and Restraints 99restraints. 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.
{ WarningChildren 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.
Never leave children unattended
in a vehicle and never allow
children to 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's 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.
{ WarningNever 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 is not
possible to hold it during a crash.
For example, in a crash at only
40 km/h (25 mph), a 5.5 kg (12 lb)
infant will suddenly become a
110 kg (240 lb) force on a person's
arms. An infant or child should be
secured in an appropriate
restraint. { WarningChildren who are up against,
or very close to, any airbag when
it inflates can be seriously injured
or killed. Never put a rear-facing
child restraint in the front
outboard seat. Secure a
rear-facing child restraint in a rear
seat. It is also better to secure a
forward-facing child restraint in a
rear seat. If you must secure a
forward-facing child restraint in
the front outboard seat, always
move the front passenger seat as
far back as it will go.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
108 Seats and Restraints
{ WarningTo reduce the risk of serious or
fatal injuries during a crash, do
not attach more than one child
restraint to a single anchor.
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. A child or others
could be injured.
{ WarningChildren 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
(Continued) Warning (Continued) 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 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.
(Continued) Caution (Continued) Do not fold the rear seatback
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.
The vehicle is equipped with a front
center airbag in the inboard side of
the driver seat. Even with a front
center airbag, a child restraint can
be installed in any second row
seating position.
If you need to secure more than one
child restraint in the rear seat, see
Where to Put the Restraint 0 102 .
This system is designed to make
installation of child restraints easier.
When using lower anchors, do not
use the vehicle's seat belts. Instead
use the vehicle's anchors and child
restraint attachments to secure the

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Seats and Restraints 111Head Restraint Removal and
Reinstallation 1. Partially fold the seatback
forward. See Third Row Seats
0 74 for additional information.
2. Press the buttons on the head
restraint posts and pull up on
the head restraint.
3. Route the top tether of the child
restraint under the head
restraint. 4. With the head restraint facing
rearward, insert the head
restraint posts into the holes in
the top of the seatback.
5. Push the head restraint down.
6. Try to move the head restraint
to make sure that it is locked in
place.
7. When the child restraint is
removed, reinstall the head
restraint before the seating
position is used.{ WarningWith 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.
Replacing LATCH System
Parts After a Crash
{ WarningA 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
(Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Seats and Restraints 1133. Push the latch plate into the
buckle until it clicks.
If the latch plate will not go fully
into the buckle, check to see if
the correct buckle is
being used.
Position the release button on
the buckle, away from the child
restraint system, so that the
seat belt could be quickly
unbuckled if necessary.
4. Pull the shoulder belt all the
way out of the retractor to set
the lock. When the retractor lock is set, the belt can be
tightened but not pulled out of
the retractor.
5. To tighten the belt, push down
on the child restraint, pull the
shoulder portion of the belt to
tighten the lap portion of the
belt and feed the shoulder belt
back into the retractor. When
installing a forward-facing child
restraint, it may be helpful to
use your knee to push down on
the child restraint as you
tighten the belt. Try to pull the belt out of the
retractor to make sure the
retractor is locked. If the
retractor is not locked, repeat
Steps 4 and 5.
6. If the child restraint has a top
tether, follow the child restraint
manufacturer ’ s instructions
regarding the use of the top
tether. Refer to the instructions
that came with the child
restraint and see Lower
Anchors and Tethers for
Children (LATCH System)
0 104 .
7. Before placing a child in the
child restraint, make sure it is
securely held in place. To
check, grasp the child restraint
at the seat belt path and
attempt to move it side to side
and back and forth. When the
child restraint is properly
installed, there should be no
more than 2.5 cm (1 in) of
movement.