roof GMC SIERRA 2020 Owner's Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 9
Keys, Doors, and
Windows
Keys and Locks
Keys (Key Access) . . . . . . . . . . . . . . 9
Keys (Keyless Access) . . . . . . . . 12
Remote Keyless Entry (RKE)System . . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Key
Access) . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Keyless
Access) . . . . . . . . . . . . . . . . . . . . . . 15
Remote Vehicle Start . . . . . . . . . . 24
Door Locks . . . . . . . . . . . . . . . . . . . . 25
Power Door Locks . . . . . . . . . . . . . 26
Delayed Locking . . . . . . . . . . . . . . . 26
Automatic Door Locks . . . . . . . . . 26
Lockout Protection . . . . . . . . . . . . . 27
Safety Locks . . . . . . . . . . . . . . . . . . . 27
Doors
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . 28
Power Assist Steps . . . . . . . . . . . . 36
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . 37
Vehicle Alarm System . . . . . . . . . 37 Steering Column Lock . . . . . . . . . 38
Immobilizer . . . . . . . . . . . . . . . . . . . . 39
Immobilizer Operation . . . . . . . . . 39
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . 40
Manual Mirrors . . . . . . . . . . . . . . . . . 41
Trailer-Tow Mirrors . . . . . . . . . . . . . 41
Power Mirrors . . . . . . . . . . . . . . . . . . 43
Folding Mirrors . . . . . . . . . . . . . . . . . 43
Heated Mirrors . . . . . . . . . . . . . . . . . 44
Automatic Dimming Mirror . . . . . 44
Blind Spot Mirrors . . . . . . . . . . . . . . 44
Reverse Tilt Mirrors . . . . . . . . . . . . 45
Interior Mirrors
Interior Rearview Mirrors . . . . . . . 46
Manual Rearview Mirror . . . . . . . . 46
Automatic Dimming Rearview
Mirror . . . . . . . . . . . . . . . . . . . . . . . . . 46
Rear Camera Mirror . . . . . . . . . . . . 46
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . 48
Manual Windows . . . . . . . . . . . . . . 49
Power Windows . . . . . . . . . . . . . . . 49
Rear Windows . . . . . . . . . . . . . . . . . 51
Sun Visors . . . . . . . . . . . . . . . . . . . . . 51
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . 51
Keys and Locks
Keys (Key Access)
{Warning
Leaving children in a vehicle with
the ignition 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 keys in the
ignition, and children or others
could be caught in the path of a
closing window. Do not leave
children in a vehicle with the
ignition key.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 49
The vehicle aerodynamics are
designed to improve fuel economy
performance. This may result in a
pulsing sound when either rear
window is down and the front
windows are up. To reduce the
sound, open either a front window
or the sunroof, if equipped.
Manual Windows
If equipped, turn the hand crank on
each door to manually raise or lower
the manual windows.
Power Windows
{Warning
Children could be seriously
injured or killed if caught in the
path of a closing window. Never
leave the Remote Keyless Entry
(RKE) transmitter or keys in a
vehicle with children. When there
are children in the rear seat, use
the window lockout button to(Continued)
Warning (Continued)
prevent operation of the windows.
SeeKeys (Key Access) 09or
Keys (Keyless Access) 012.
The power windows work when the
ignition is on, in ACC/ACCESSORY,
or when Retained Accessory Power
(RAP) is active. See Retained
Accessory Power (RAP) 0217.
Using the window switch, press to
open or pull to close the window. The windows may be temporarily
disabled if they are used repeatedly
within a short time.
Window Lockout
With Power Folding Mirrors,
Without Similar
This feature stops the rear door
passenger window switches from
working except from the driver
position.
Press
2to engage the rear
window lockout feature. The
indicator light is on when engaged.
Press
2again to disengage.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 51
Rear Windows
Power Sliding Rear Window
If equipped, the power sliding rear
window works when the ignition has
been turned on or to ACC/
ACCESSORY, or Retained
Accessory Power (RAP) must be
active. SeeRetained Accessory
Power (RAP) 0217.
. Press the switch to open the
window.
. Pull the switch to close the
window. The power sliding rear window
cannot be operated manually.
Sun Visors
Pull the sun visor down to block
glare. If equipped, detach the sun
visor from the center mount to pivot
to the side window or to extend
along the rod.
If equipped, there is a lighted mirror
on the sun visor. Lift the cover
to open.
Roof
Sunroof
1. SLIDE Switch
2. TILT Switch
If equipped, the sunroof operates
when the ignition is on or in ACC/
ACCESSORY, or when Retained
Accessory Power (RAP) is active.
See
Retained Accessory Power
(RAP) 0217.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
52 Keys, Doors, and Windows
Slide Switch
Express-Open/Express-Close :To
express-open the sunroof, fully
press and release
I(1). Press and
release
I(1) again to stop the
movement. To express-close the
sunroof, fully press and release
K
(1). Press and releaseK(1)
again to stop the movement.
Open/Close (Manual Mode) : To
open the sunroof, press and hold
I
(1). ReleaseI(1) to stop the
movement. Press and hold
K(1)
to close the sunroof. Release
K
(1) to stop the movement.
Tilt Switch
Vent : From the closed position,
press
J(2) to vent the sunroof.
Press
K(2) to close the vent.
When the sunroof is opened, an air
deflector will automatically raise.
The air deflector will retract when
the sunroof is closed. The sunroof also has a sunshade,
which can be pulled forward to block
sun rays. The sunshade must be
opened and closed manually.
Automatic Reversal System
The sunroof has an automatic
reversal system that is only active
when the sunroof is operated in
express-close mode.
If an object is in the path while
express-closing, the reversal system
will detect an object, stop, and open
the sunroof again.
If frost or other conditions prevent
closing, override the feature by
closing the sunroof in manual mode.
To stop movement, release
K(1).
Dirt and debris may collect on the
sunroof seal or in the track. This
could cause an issue with sunroof
operation or noise. It could also plug
the water drainage system.
Periodically open the sunroof and
remove any obstacles or loose
debris. Wipe the sunroof seal and
roof sealing area using a clean
cloth, mild soap, and water. Do not
remove grease from the sunroof
tracks.
If water is seen dripping into the
water drainage system, this is
normal.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
72 Seats and Restraints
{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,(Continued)
Warning (Continued)
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 0136.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 73
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.
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(Continued)
Warning (Continued)
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. See When
Should an Airbag Inflate? 076.
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
(Continued)
Warning (Continued)
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 75
Driver Side Shown, PassengerSide 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 (Continued)
Warning (Continued)
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 do not attach or put
anything on the steering wheel
hub or on or near any other
airbag covering.
Do not use seat accessories that
block the inflation path of a
seat-mounted side impact airbag.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
76 Seats and Restraints
When Should an Airbag
Inflate?
This vehicle is equipped with
airbags. SeeAirbag System 072.
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.
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 77
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, seeWhere Are
the Airbags? 074.
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? 076.
Airbags should never be regarded
as anything more than a supplement
to seat belts.
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. 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? 074.
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.
{Warning
When 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
84 Seats and Restraints
of the seat fabric, could also
interfere with the operation of the
passenger sensing system. This
could either prevent proper
deployment of the passenger
airbag(s) or prevent the passenger
sensing system from properly
turning off the passenger airbag(s).
SeePassenger Sensing System
0 78.
If the vehicle has rollover roof-rail
airbags, see Different Size Tires
and Wheels 0401 for additional
important information.
If a snow plow is added to the
vehicle, the airbags should still work
properly. The airbag systems were
designed to work properly under a
wide range of conditions, including
snow plowing with vehicles that
have the optional snow plow prep
package (RPO VYU). Do not
change or defeat the snow plow's
“tripping mechanism.” If you do, it
can damage the snow plow and the
vehicle, and may cause an airbag
deployment. If the vehicle must be modified
because you have a disability and
have questions about whether the
modifications will affect the vehicle's
airbag system, or if you have
questions about whether the airbag
system will be affected if the vehicle
is modified for any other reason, call
Customer Assistance. See
Customer Assistance Offices
0465.
Airbag System Check
The airbag system does not need
regularly scheduled maintenance or
replacement. Make sure the airbag
readiness light is working. See
Airbag Readiness Light 0136.
Caution
If an airbag covering is damaged,
opened, or broken, the airbag
may not work properly. Do not
open or break the airbag
coverings. If there are any
opened or broken airbag
coverings, have the airbag
(Continued)
Caution (Continued)
covering and/or airbag module
replaced. For the location of the
airbags, seeWhere Are the
Airbags? 074. See your dealer
for service.
Replacing Airbag System
Parts after a Crash
{Warning
A crash can damage the airbag
systems in the vehicle.
A damaged airbag system may
not properly protect you and your
passenger(s) in a crash, resulting
in serious injury or even death. To
help make sure the airbag
systems are working properly
after a crash, have them
inspected and any necessary
replacements made as soon as
possible.