2018 GMC SIERRA Owner's Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
48 Keys, Doors, and Windows
Using hood-mounted air deflectors
and add-on convex mirror
attachments could decrease mirror
performance.
Trailer-Tow Mirrors
If equipped, adjust trailer-tow
mirrors for a clear view of the area
behind you. Manually pull out the
mirror head to extend it for better
visibility when towing a trailer.
The lower portion of the mirror is
convex. A convex mirror's surface is
curved to see more from the driverseat. The convex mirror can be
adjusted manually to the driver
preferred position for better vision.
The mirror may have a turn signal
arrow that flashes in the direction of
the turn or lane change.
Power Mirrors
Using hood-mounted air deflectors
and add-on convex mirror
attachments could decrease mirror
performance.
Base Power Mirrors
The power mirror controls are on the
driver door. 1. Press (1) or (2) to select the
driver or passenger side mirror.
2. Press one of the four arrows on the control pad to move the
mirror in the desired direction.
3. Adjust each outside mirror so that a little of the vehicle and
the area behind it can be seen.
4. Move the selector switch to the center position when not
adjusting either outside mirror.Crew/Double Cab Premium
Shown, Other Models Similar
1. Press (1) or (2) to select the driver or passenger side mirror.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 49
2. Press one of the four arrows onthe control pad while the
indicator light on button (1)
or (2) is illuminated, to move
the mirror in the desired
direction.
3. Adjust each outside mirror so that a little of the vehicle and
the area behind it can be seen.
4. Press either (1) or (2) again to deselect the mirror.
If you do not deselect the mirror, the
feature will turn off after about
one minute.
The mirrors may include a memory
function that works with the memory
seats. See Memory Seats 062.Folding Mirrors
Crew/Double Cab Premium Trim
Shown, Other Models Similar
Power Folding
If equipped with power folding
mirrors:
1. Press (2) to fold the mirrors out to the driving position.
2. Press (2) again to fold the mirrors in to the folded position.
The mirrors may also include a
memory function that works with the
memory seats. See Memory Seats
0 62. Resetting the Power Folding
Mirrors
Reset the power folding mirrors if:
.
The mirrors are accidentally
obstructed while folding.
. They are accidentally manually
folded/unfolded.
. The mirrors will not stay in the
unfolded position.
. The mirrors vibrate at normal
driving speeds.
Manually fold both mirrors if they
are out of sync. Fold and unfold the
mirrors three times using the mirror
controls to reset them to their
normal position. A popping noise
may be heard. This sound is normal
after a manual folding operation.
Manual Folding
If equipped, push the mirror toward
the vehicle to fold. Push the mirror
outward to return to its original
position.
Manually fold the mirrors inward to
prevent damage when going
through an automatic car wash.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
50 Keys, Doors, and Windows
Auto Mirror Folding
If equipped, with the ignition off,
press and hold
Qon the RKE
transmitter for approximately
one second to automatically fold the
exterior mirrors. Press and hold
K
on the RKE transmitter for
approximately one second to unfold.
See Remote Keyless Entry (RKE)
System Operation 037.
This feature is turned on or off
through vehicle personalization. See
Vehicle Personalization 0165.
Turn Signal Indicator
If equipped, indicator lights on the
mirror flash in the direction of the
turn or lane change.
Heated Mirrors
If equipped with heated mirrors:
K:Press to heat the outside
mirrors. If the vehicle has trailer-tow
mirrors, only the upper glass of the
mirror is heated. The lower convex
part of the trailer-tow mirrors is not
heated. See
“Rear Window Defogger” under
Dual Automatic Climate Control
System 0228.
Automatic Dimming
Mirror
If equipped, the driver outside mirror
automatically adjusts for the glare of
the headlamps from behind. This
feature comes on when the vehicle
is started.
Blind Spot Mirrors
If equipped, there is a small convex
mirror built into the upper and outer
corner of the driver outside mirror.
It can show objects that may be in
the vehicle's blind zone.
Driving with the Blind Spot
Mirror
Actual Mirror View

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 51
1. When the approaching vehicleis a long distance away, the
image in the main mirror is
small and near the inboard
edge of the mirror.
2. As the vehicle gets closer, the image in the main mirror gets
larger and moves outboard.
3. As the vehicle enters the blind zone, the image transitions
from the main mirror to the
blind spot mirror.
4. When the vehicle is in the blind zone, the image only appears
in the blind spot mirror.
Using the Outside Mirror with
the Blind Spot Mirror
1. Set the main mirror so that theside of the vehicle can just be
seen and the blind spot mirror
has an unobstructed view.
2. When checking for traffic or before changing a lane, look at
the main driver/passenger side
mirror to observe traffic in the
adjacent lane, behind your
vehicle. Check the blind spot mirror for a vehicle in the blind
zone. Then, glance over your
shoulder to double check
before moving slowly into the
adjacent lane.
Reverse Tilt Mirrors
If equipped with memory seats, the
passenger and/or driver mirror tilts
to a preselected position when the
vehicle is in R (Reverse). This
allows the curb to be seen when
parallel parking.
The mirror(s) return to the original
position when:
.
The vehicle is shifted out of
R (Reverse), or remains in
R (Reverse) for about
30 seconds.
. The ignition is turned off.
. The vehicle is driven in
R (Reverse) above a set speed.
To turn this feature on or off, see
Vehicle Personalization 0165.
Interior Mirrors
Interior Rearview Mirrors
Adjust the rearview mirror for a clear
view of the area behind your
vehicle.
If equipped with OnStar, the vehicle
may have three control buttons at
the bottom of the mirror. See your
dealer for more information about
OnStar and how to subscribe to it.
See OnStar Overview 0479.
Do not spray glass cleaner directly
on the mirror. Use a soft towel
dampened with water.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
52 Keys, Doors, and Windows
Manual Rearview Mirror
If equipped, push the tab forward for
daytime use and pull it rearward for
nighttime use to avoid glare from
the headlamps from behind.
Automatic Dimming
Rearview Mirror
The mirror will automatically reduce
the glare of the headlamps from
behind. The dimming feature comes
on each time the vehicle is started.
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.
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
prevent operation of the windows.
SeeKeys 034.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 53
Crew/Double Cab Premium TrimShown, Other Models Similar
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) 0260.
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
Crew/Double Cab Premium
Shown, Other Models Similar
This feature stops the rear door
passenger window switches from
working except from the driver
position.
Press
Zto engage the rear
window lockout feature. The
indicator light is on when engaged.
Press
Zagain to disengage.
Window 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.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
54 Keys, Doors, and Windows
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.
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. See Retained Accessory
Power (RAP) 0260.
. Press the switch to open the
window.
. Pull the switch to close the
window.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 55
The power sliding rear window
cannot be operated manually.
Sun Visors
Pull the sun visor down to block
glare. Detach the sun visor from the
center mount to pivot to the side
window and, if equipped, extend
along the rod.
Roof
Sunroof
If equipped, the sunroof operates
when the ignition is on or in ACC/
ACCESSORY, or when Retained
Accessory Power (RAP) is active.
SeeRetained Accessory Power
(RAP) 0260.
Slide Switch
Express-Open/Express-Close : To
express-open the sunroof, fully
press and release
I. Press the
switch again to stop the movement. To express-close the sunroof, fully
press and release
K. Press the
switch again to stop the movement.
Open/Close (Manual Mode) : To
open the sunroof, press and
hold
I. Release the switch to stop
the movement. Press and hold
K
to close the sunroof. Release the
switch to stop the movement.
Tilt Switch
Vent : From the closed position,
press
Jto vent the sunroof. Press
Kto 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.