
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Introduction 3
Danger, Warning, and
Caution Warning messages found on vehicle
labels and in this manual describe
hazards and what to do to avoid or
reduce them.
{ DangerDanger indicates a hazard with a
high level of risk which will result
in serious injury or death.
{ WarningWarning indicates a hazard that
could result in injury or death.
Caution
Caution indicates a hazard that
could result in property or vehicle
damage. 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.
9 : Airbag Readiness Light
# : Air Conditioning
! : Antilock Brake System (ABS)
$ : Brake System Warning Light
" : Charging System
I : Cruise Control
` : Do Not Puncture
^ : Do Not Service
B : Engine Coolant Temperature
O : Exterior Lamps
_ : Flame/Fire Prohibited
. : Fuel Gauge
+ : Fuses
3 : Headlamp High/Low-Beam
Changer
j : ISOFIX/LATCH System Child
Restraints

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
In Brief 71. Instrument Panel Illumination
Control 0 182 .
2. Integrated Trailer Brake Control
(ITBC) System (If Equipped).
See Towing Equipment 0 325 .
3. Exterior Lamp Controls 0 176 .
Fog Lamps 0 181 (If
Equipped).
4. Air Vents 0 231 .
5. Turn Signal Lever. See Turn
and Lane-Change Signals
0 181 .
Windshield Wiper/Washer
0 130 .
6. Favorite Switches (Out of
View). See Steering Wheel
Controls 0 129 .
Volume Switches (Out of View).
See Steering Wheel Controls
0 129 .
7. Instrument Cluster 0 138 .
8. Hazard Warning Flashers
0 180 .
9. Shift Lever. See Automatic
Transmission 0 265 . Tow/Haul Selector Button (If
Equipped). See Tow/Haul
Mode 0 271 .
Range Selection Mode (If
Equipped). See Manual Mode
0 268 .
10. Light Sensor. See Automatic
Headlamp System 0 179 .
11. Infotainment 0 186 .
12. Passenger Airbag On-Off
Switch (If Equipped) (Out of
View). See Airbag On-Off
Switch 0 84 .
13. Heated and Ventilated Front
Seats 0 65 (If Equipped).
14. Power Outlet 110/120V
Alternating Current (If
Equipped). See Power Outlets
0 133 .
15. Power Outlets 0 133 (If
Equipped).
16. USB Port 0 197 (If Equipped).
17.
g Traction Control/Electronic
Stability Control 0 282 .0 Pedal Adjust Switch (If
Equipped). See Adjustable
Throttle and Brake Pedal
0 256 .
{ Cargo Lamp 0 183 .
X Parking Assist Button (If
Equipped). See Assistance
Systems for Parking or Backing
0 289 .
A Lane Keep Assist (LKA)
(1500 Series) 0 297 (If
Equipped).
5 Hill Descent Control Switch
(If Equipped). See Hill Descent
Control (HDC) 0 284 .
q Exhaust Brake Switch (If
Equipped). See “ Exhaust
Brake ” in the Duramax diesel
supplement.
g Power Take Off (PTO)
Switch (If Equipped). See the
Duramax diesel supplement.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
14 In Brief Press
C to ventilate the driver or
passenger seat.
See Heated and Ventilated Front
Seats 0 65 .
Head Restraint
Adjustment Do not drive until the head restraints
for all occupants are installed and
adjusted properly.
To achieve a comfortable seating
position, change the seatback
recline angle as little as necessary
while keeping the seat and the head
restraint height in the proper
position.
See Head Restraints 0 58 and
Power Seat Adjustment 0 60 .Seat Belts
Refer to the following sections for
important information on how to use
seat belts properly:
.
Seat Belts 0 69 .
.
How to Wear Seat Belts Properly
0 70 .
.
Lap-Shoulder Belt 0 71 .
.
Lower Anchors and Tethers for
Children (LATCH System) 0 99 .Passenger Sensing
System The passenger sensing system,
if equipped, turns off the front
outboard passenger frontal airbag
under certain conditions. No other
airbag is affected by the passenger
sensing system.
If the vehicle has one of the
indicators pictured in the following
illustrations, then the vehicle has a
passenger sensing system for the
front outboard passenger position
unless there is an airbag off switch
on the instrument panel endcap.
If there is an airbag off switch, the
vehicle does not have a passenger
sensing system. See Airbag On-Off
Switch 0 84 for more information.
The passenger airbag status
indicator will be visible on the
overhead console when the vehicle
is started.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 35
{ WarningIf 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
(Continued) Warning (Continued) 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Seats and Restraints 57
Seats and
Restraints Head Restraints Head Restraints . . . . . . . . . . . . . . . 58
Front Seats Seat Adjustment . . . . . . . . . . . . . . . 59
Center Seat . . . . . . . . . . . . . . . . . . . . 59
Power Seat Adjustment . . . . . . . . 60
Lumbar Adjustment . . . . . . . . . . . . 60
Reclining Seatbacks . . . . . . . . . . . 61
Memory Seats . . . . . . . . . . . . . . . . . 62
Heated and Ventilated Front
Seats . . . . . . . . . . . . . . . . . . . . . . . . . 65
Rear Seats Rear Seats (Double Cab Full
Bench) . . . . . . . . . . . . . . . . . . . . . . . 66
Rear Seats (Split Bench) . . . . . . 68
Seat Belts Seat Belts . . . . . . . . . . . . . . . . . . . . . 69
How to Wear Seat Belts
Properly . . . . . . . . . . . . . . . . . . . . . . 70
Lap-Shoulder Belt . . . . . . . . . . . . . 71
Seat Belt Use During
Pregnancy . . . . . . . . . . . . . . . . . . . . 74
Lap Belt . . . . . . . . . . . . . . . . . . . . . . . 75 Seat Belt Extender . . . . . . . . . . . . . 75
Safety System Check . . . . . . . . . . 75
Seat Belt Care . . . . . . . . . . . . . . . . . 76
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 76
Airbag System Airbag System . . . . . . . . . . . . . . . . . 77
Where Are the Airbags? . . . . . . . 78
When Should an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . . 80
What Makes an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . . 82
How Does an Airbag
Restrain? . . . . . . . . . . . . . . . . . . . . . 82
What Will You See after an
Airbag Inflates? . . . . . . . . . . . . . . 82
Airbag On-Off Switch . . . . . . . . . . 84
Passenger Sensing System . . . 86
Servicing the Airbag-Equipped
Vehicle . . . . . . . . . . . . . . . . . . . . . . . 90
Adding Equipment to the
Airbag-Equipped Vehicle . . . . . 90
Airbag System Check . . . . . . . . . . 91
Replacing Airbag System Parts
after a Crash . . . . . . . . . . . . . . . . . 92
Child Restraints
Older Children . . . . . . . . . . . . . . . . . 92
Infants and Young Children . . . . 94
Child Restraint Systems . . . . . . . 96 Where to Put the Restraint . . . . . 98
Lower Anchors and Tethers for
Children (LATCH System) . . . . 99
Replacing LATCH System
Parts After a Crash . . . . . . . . . . 111
Securing Child Restraints (With
the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 111
Securing Child Restraints (With
the Seat Belt in the Center
Front Seat) . . . . . . . . . . . . . . . . . . 114
Securing Child Restraints (With
the Seat Belt in the Front
Passenger Seat) . . . . . . . . . . . . 115

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
70 Seats and Restraints This system may not function
properly if the airbag readiness light
is on. See Airbag Readiness Light
0 147 .
Why Seat Belts Work
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 a crash 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
can unbuckle 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 with
seat 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 This section is only for people of
adult size.
There are special things to know
about seat belts and children, and
there are different rules for smaller
children and infants. If a child will be
riding in the vehicle, see Older
Children 0 92 or Infants and Young
Children 0 94 . Follow those rules for
everyone's protection.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
74 Seats and Restraints 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. And, if your
vehicle has side impact airbags,
seat belt pretensioners can help
tighten the seat belts in a side
crash. If the vehicle has rollover
roof-rail airbags, seat belt
pretensioners can help tighten the
seat belts in 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 76 . 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.
Rear Seat Belt Comfort Guides Rear seat belt comfort guides may
provide added seat belt comfort for
older children who have outgrown
booster seats and for some adults.
When installed on a shoulder belt,
the comfort guide positions the
shoulder belt away from the neck
and head.
Comfort guides are available
through your dealer for the rear
outboard seating positions.
Instructions are included with the
guide.
Seat Belt Use During
Pregnancy Seat belts work for everyone,
including pregnant women. Like all
occupants, they are more likely to
be seriously injured if they do not
wear seat belts. A pregnant woman should wear a
lap-shoulder belt, and the lap
portion should be worn as low as
possible, below the rounding,
throughout the pregnancy.
The best way to protect the fetus is
to protect the mother. When a seat
belt is worn properly, it is more likely
that the fetus will not be hurt in a
crash. For pregnant women, as for
anyone, the key to making seat
belts effective is wearing them
properly.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
76 Seats and Restraints Make sure the seat belt reminder
light is working. See Seat Belt
Reminders 0 146 .
Keep seat belts clean and dry. See
Seat Belt Care 0 76 .
Seat Belt Care Keep belts clean and dry.
{ WarningDo 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.
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.
Replacing Seat Belt
System Parts after a
Crash
{ WarningA 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 0 147 .