2020 GMC SIERRA warning

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
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 57
To adjust the lumbar support, see
Lumbar Adjustment057.
Some vehicles are equipped with a
feature that activates a vibrating
pulse alert in the driver seat to help
the driver avoid crashes. See Driver
Assistance Systems 0256.
Lumbar Adjustment
Power Lumbar
To adjust the lumbar support,
if equipped: .
Press and hold the control
forward to increase or rearward
to decrease upper and lower
lumbar support at the same time.
Reclining Seatbacks
{Warning
Sitting in a reclined position when
the vehicle is in motion can be
dangerous. Even when buckled
up, the seat belts cannot do
their job.
The shoulder belt will not be
against your body. Instead, it will
be in front of you. In a crash, you
could go into it, receiving neck or
other injuries.
The lap belt could go up over
your abdomen. The belt forces
would be there, not at your pelvic
bones. This could cause serious
internal injuries.
(Continued)
Warning (Continued)
For proper protection when the
vehicle is in motion, have the
seatback upright. Then sit well
back in the seat and wear the
seat belt properly.
Do not have a seatback reclined if
the vehicle is moving.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
58 Seats and Restraints
Manual Reclining Seatbacks
{Warning
If either seatback is not locked, it
could move forward in a sudden
stop or crash. That could cause
injury to the person sitting there.
Always push and pull on the
seatbacks to be sure they are
locked.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 61
memory button number 1 or 2 are
automatically recalled when the
vehicle is turned on, or turned from
off to ACC/ACCESSORY. RKE
transmitters 3–8 will not provide
automatic memory recalls.
To turn Seat Entry Memory on or off,
see“Vehicle Personalization
Settings” previously in this section
and Vehicle Personalization 0157.
The shift lever must be in P (Park)
to start Seat Entry Memory. Seat
Entry Memory recall will complete if
the vehicle is shifted out of P (Park)
prior to reaching the saved memory
position.
To stop Seat Entry Memory recall
movement, turn the vehicle off or
press any of the following controls:
. Power seat
. Memory SET, 1, 2, or
B
.Power mirror, with the driver or
passenger side mirror selected
If the saved memory seat position
does not automatically recall or
recalls to the wrong positions, the
driver ’s RKE transmitter number (1 or 2) may not match the memory
button number that positions were
saved to. Try storing the position to
the other memory button or try the
other RKE transmitter.
Seat Exit Memory
Seat Exit Memory is not linked to an
RKE transmitter. The position saved
to
Bis used for all drivers. To turn
Seat Exit Memory on or off, see
"Vehicle Personalization Settings"
previously in this section and
Vehicle Personalization 0157.
If turned on, the position saved to
Bis automatically recalled when
one of the following occurs:
. The vehicle is turned off and the
driver door is opened within a
short time.
. The vehicle is turned off with the
driver door open.
To stop Seat Exit Memory
movement, press any of the
following memory controls:
. Power seat
. Memory SET, 1, 2, or
B
.
Power mirror, with the driver or
passenger side mirror selected
Obstructions
If something has blocked the driver
seat while recalling a memory
position, the recall may stop.
Remove the obstruction and try the
recall again. If the memory position
still does not recall, see your dealer.
Heated and Ventilated
Front Seats
{Warning
If temperature change or pain to
the skin cannot be felt, the seat
heater may cause burns. To
reduce the risk of burns, use care
when using the seat heater,
especially for long periods of
time. Do not place anything on
the seat that insulates against
heat, such as a blanket, cushion,
cover, or similar item. This may
cause the seat heater to (Continued)