2020 GMC SIERRA Owner's Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
48 Keys, Doors, and Windows
Troubleshooting
See your dealer for service if a blue
screen and
3are displayed in
the mirror, and the display shuts off.
Also, push the tab as indicated to
return to the automatic
dimming mode.
The Rear Camera Mirror may not
work properly or display a clear
image if:
. There is glare from the sun or
headlamps. This may obstruct
objects from view. If needed,
push the tab to turn off the
display. .
Dirt, snow, or other debris blocks
the camera lens. Clean the lens
with a soft damp cloth.
. The camera’s mounting on the
vehicle has been damaged, and/
or the position or the mounting
angle of the camera has
changed.
Windows
{Warning
Never leave a child, a helpless
adult, or a pet alone in a vehicle,
especially with the windows
closed in warm or hot weather.
They can be overcome by the
extreme heat and suffer
permanent injuries or even death
from heat stroke.

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
50 Keys, Doors, and Windows
Windows Express Movement
All windows can be opened without
holding the window switch. Press
the switch down fully and quickly
release to express open the
window.
If equipped, pull the window switch
up fully and quickly release to
express close the window.
Briefly press or pull the window
switch in the same direction to stop
that window’s express movement.
Express Window Down
L: If equipped, this button will be
on the center stack.
Press and hold
Lto open all
windows. Release
Lto stop all
movement.
Use the power window switches to
close each window.
Window Automatic Reversal
System
The express-close feature will
reverse window movement if it
comes in contact with an object. Extreme cold or ice could cause the
window to auto-reverse. The
window will operate normally after
the object or condition is removed.
Automatic Reversal System
Override
{Warning
If automatic reversal system
override is active, the window will
not reverse automatically. You or
others could be injured and the
window could be damaged.
Before using automatic reversal
system override, make sure that
all people and obstructions are
clear of the window path.
When the engine is on, override the
automatic reversal system by pulling
and holding the window switch if
conditions prevent it from closing.
Programming the Power
Windows
Programming may be necessary if
the vehicle battery has been
disconnected or discharged. If the
window is unable to express-up,
program each express-close
window: 1. Close all doors.
2. Turn the ignition on or to ACC/ ACCESSORY.
3. Partially open the window to be programmed. Then close it and
continue to pull the switch
briefly after the window has
fully closed.
4. Open the window and continue to press the switch briefly after
the window has fully opened.
Remote Window Operation
If equipped, this feature allows the
windows to be opened remotely.
If enabled in vehicle personalization,
press and hold
Kon the RKE
transmitter. See Vehicle
Personalization 0157.

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
Seats and Restraints 53
Seats and
Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . 54
Front Seats
Seat Adjustment . . . . . . . . . . . . . . . 55
Center Seat . . . . . . . . . . . . . . . . . . . . 56
Power Seat Adjustment . . . . . . . . 56
Lumbar Adjustment . . . . . . . . . . . . 57
Reclining Seatbacks . . . . . . . . . . . 57
Memory Seats . . . . . . . . . . . . . . . . . 59
Heated and Ventilated FrontSeats . . . . . . . . . . . . . . . . . . . . . . . . . 61
Rear Seats
Rear Seats . . . . . . . . . . . . . . . . . . . . 63
Heated Rear Seats . . . . . . . . . . . . 64
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . 65
How to Wear Seat BeltsProperly . . . . . . . . . . . . . . . . . . . . . . 66
Lap-Shoulder Belt . . . . . . . . . . . . . 68
Seat Belt Use During Pregnancy . . . . . . . . . . . . . . . . . . . . 70
Seat Belt Extender . . . . . . . . . . . . . 71
Safety System Check . . . . . . . . . . 71 Seat Belt Care . . . . . . . . . . . . . . . . . 71
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 72
Airbag System
Airbag System . . . . . . . . . . . . . . . . . 72
Where Are the Airbags? . . . . . . . 74
When Should an AirbagInflate? . . . . . . . . . . . . . . . . . . . . . . . 76
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . 76
How Does an Airbag Restrain? . . . . . . . . . . . . . . . . . . . . . 77
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . . 77
Passenger Sensing System . . . 78
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . 83
Adding Equipment to the Airbag-Equipped Vehicle . . . . . 83
Airbag System Check . . . . . . . . . . 84
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . 84
Child Restraints
Older Children . . . . . . . . . . . . . . . . . 85
Infants and Young Children . . . . 87
Child Restraint Systems . . . . . . . 89
Where to Put the Restraint . . . . . 91
Lower Anchors and Tethers forChildren (LATCH System) . . . . 92 Replacing LATCH System
Parts After a Crash . . . . . . . . . 105
Securing Child Restraints (With the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 105
Securing Child Restraints (In the Center Front Seat) . . . . . . 108
Securing Child Restraints (With the Seat Belt in the Front
Outboard Seat) . . . . . . . . . . . . . 109

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
54 Seats and Restraints
Head 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.
Front Seats
The vehicle's front seats have
adjustable head restraints in the
outboard seating positions.
Adjust the head restraint so that the
top of the restraint is at the same
height as the top of the occupant's
head. This position reduces the
chance of a neck injury in a crash.To raise or lower the head restraint,
press the button on the side of the
head restraint and pull up or push
the head restraint down and release
the button.
Pull and push on the head restraint
after the button is released to make
sure that it is locked in place.
The front seat outboard head
restraints are not removable.
Rear Head Restraints
The vehicle’s rear seat has head
restraints in the outboard seating
positions that cannot be adjusted.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 55
The head restraint can be folded
forward to allow for better visibility
when the rear seat is unoccupied.
To fold the head restraint, press the
button on the side of the head
restraint.
When an occupant is in the seat,
always return the head restraint to
the upright position until it locks into
place. Push and pull on the head
restraint to make sure that it is
locked.
If you are installing a child restraint
in the rear seat, seeLower Anchors
and Tethers for Children (LATCH
System) 092. 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) 092.
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.