2024 GMC SIERRA warning

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
34 Keys, Doors, and Windows
The security light, in the instrument cluster,
comes on if there is a problem with arming
or disarming the theft-deterrent system.
The system has one or more remote keys
matched to an immobilizer control unit in
your vehicle. Only a correctly matched
remote key will start the vehicle. If the
remote key is ever damaged, you may not
be able to start your vehicle.
When trying to start the vehicle, the
security light may come on briefly when the
ignition is turned on. If the engine does not
start and the security light stays on, there is
a problem with the system. Turn the
ignition off and try again.
If the vehicle will not change ignition modes
(accessory mode, on, off), and the remote
key appears to be undamaged, try another
remote key. Or, you may try placing the
remote key in the remote key pocket
located in the center console. SeeRemote
Key Operation 015.
If the ignition mode will not change with
the other remote key or with the remote
key in the remote key pocket, your vehicle
needs service. If the ignition does change
modes, the first remote key may be faulty. See your dealer who can service the
theft-deterrent system and have a new
remote key programmed to the vehicle.
It is possible for the immobilizer system to
learn new or replacement remote keys. Up
to eight remote keys can be programmed
for the vehicle. To program additional
remote keys, see "Programming Remote
Keys to the Vehicle" under
Remote Key
Operation 015.
Do not leave the remote key or device that
disarms or deactivates the vehicle theft
system in the vehicle.
Exterior Mirrors
Convex Mirrors
{Warning
A convex mirror can make things, like
other vehicles, look farther away than
they really are. If you cut too sharply
into the right lane, you could hit a
vehicle on the right. Check the inside
mirror or glance over your shoulder
before changing lanes. Standard Mirrors
If equipped, the passenger side mirror is
convex shaped. A convex mirror surface is
curved so more can be seen from the
driver seat.
Trailer-Tow Mirrors
The upper portion of both the driver and
passenger mirrors is flat.
The lower portion of both the driver and
passenger mirrors is convex. A convex mirror
surface is curved so more can be seen from
the driver seat. The lower portion is
adjusted manually.
Manual Mirrors
If equipped, adjust manual mirrors by
moving the mirror up and down or left to
right to see a little of the side of the vehicle
and to have a clear view behind the vehicle.
Using hood-mounted air deflectors and
add-on convex mirror attachments could
decrease mirror performance.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
40 Keys, Doors, and Windows
.Tilt
{Warning
The Rear Camera Mirror (RCM) has a
limited view. Portions of the road,
vehicles, and other objects may not be
seen. Do not drive or park the vehicle
using only this camera. Objects may
appear closer than they are. Check the
outside mirrors or glance over your
shoulder when making lane changes or
merging. Failure to use proper care may
result in injury, death, or vehicle damage.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Keys, Doors, and Windows 41
Truck Bed Camera Rearview
Mirror
If equipped, this automatic dimming mirror
provides a video image, when activated, to
allow the driver to momentarily check the
pickup bed area contents or to align and
attach a gooseneck or fifth-wheel trailer.
.Push the button at the bottom of the
mirror once to activate the display.
.Push the button a second time to zoom
the camera’s view.
.Push the button a third time to
deactivate the display.
When the vehicle is in R (Reverse) and
button has been pressed, the display will
remain on until the driver deactivates it.
When not in R (Reverse), the video image
will time out after eight seconds.
When in Zoomed Mode, the display features
guidelines to help the driver align the
vehicle when attaching a trailer. Both the
horizontal and vertical guideline’s position
can be adjusted by the driver.
To adjust the position of the horizontal
guideline, press and hold the button for
eight seconds until it starts blinking. Each
subsequent button press scrolls the position
of this line through its range of possible
settings. Once the horizontal guideline is in the
desired location, press and hold the button
for another three seconds and repeat the
above step for the vertical guideline
programing. To readjust the horizontal
location of the guidelines after adjusting the
vertical location, press and hold the button
for three seconds.
After eight seconds since the last button
press, the position of the guidelines is
locked into memory.
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 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
42 Keys, Doors, and Windows
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.
Power Windows
{Warning
Children could be seriously injured or
killed if caught in the path of a closing
window. Never leave the remote key in a
vehicle with children. When there are(Continued)
Warning (Continued)
children in the rear seat, use the window
lockout switch to prevent operation of
the windows. SeeKeys014.
The power windows work when the ignition
is on, in accessory mode, or when Retained
Accessory Power (RAP) is active. See
Retained Accessory Power (RAP) 0220.
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.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Keys, Doors, and Windows 43
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 accessory mode. 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
settings, double press and hold
Kon the
remote key. To view available settings from
the infotainment screen, touch Settings >
Vehicle > Remote Lock, Unlock, Start.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 47
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.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
48 Seats and Restraints
If you are installing a child restraint in the
rear seat, seeLower Anchors and Tethers for
Children (LATCH System) 081.
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) 081.
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.
2. Slide the seat to the desired position and release the handle.
3. Try to move the seat back and forth to be sure it is locked in place.
To adjust the seatback, see Reclining
Seatbacks 049.
To adjust the lumbar support, if equipped,
see Lumbar Adjustment 050.
Center Seat
If equipped, the center front seatback
doubles as an armrest and cupholder/
storage area for the driver and passenger
when the center front seat is not used.
Pull the strap on the side of the center
seatback to fold the center seatback. Do not
use the center seatback as a seating position
when the seatback is folded down.
To raise the seatback, push the seatback
rearward until it locks in the upright
position. Push and pull on the seatback to
make sure it is locked.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 49
Power Seat Adjustment
To adjust a power seat, if equipped:
.Move the seat forward or rearward by
sliding the control forward or rearward.
.Raise or lower the front part of the seat
cushion by moving the front of the
control up or down.
.Raise or lower the seat by moving the
rear of the control up or down.
To adjust the seatback, see Reclining
Seatbacks 049.
To adjust the lumbar support, see Lumbar
Adjustment 050. Some vehicles are equipped with a feature
that activates a vibrating pulse alert in the
driver seat to help the driver avoid crashes.
See
Advanced Driver Assistance Systems
0 252.
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.
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 recline the seatback in a moving
vehicle.
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.