GMC SIERRA DENALI 2020 Workshop Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
50 Keys, Doors, and Windows
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.
SeeRetained Accessory Power
(RAP) 0216. 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Keys, Doors, and Windows 51
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 slightly.
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 - 8/27/19
52 Seats and Restraints
Seats and
Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . 53
Front Seats
Seat Adjustment . . . . . . . . . . . . . . . 54
Center Seat . . . . . . . . . . . . . . . . . . . . 55
Power Seat Adjustment . . . . . . . . 55
Lumbar Adjustment . . . . . . . . . . . . 56
Reclining Seatbacks . . . . . . . . . . . 56
Memory Seats . . . . . . . . . . . . . . . . . 58
Heated and Ventilated FrontSeats . . . . . . . . . . . . . . . . . . . . . . . . . 60
Rear Seats
Rear Seats . . . . . . . . . . . . . . . . . . . . 62
Heated Rear Seats . . . . . . . . . . . . 63
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . 64
How to Wear Seat BeltsProperly . . . . . . . . . . . . . . . . . . . . . . 65
Lap-Shoulder Belt . . . . . . . . . . . . . 67
Seat Belt Use During Pregnancy . . . . . . . . . . . . . . . . . . . . 69
Seat Belt Extender . . . . . . . . . . . . . 70
Safety System Check . . . . . . . . . . 70 Seat Belt Care . . . . . . . . . . . . . . . . . 70
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 71
Airbag System
Airbag System . . . . . . . . . . . . . . . . . 71
Where Are the Airbags? . . . . . . . 73
When Should an AirbagInflate? . . . . . . . . . . . . . . . . . . . . . . . 75
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . 75
How Does an Airbag Restrain? . . . . . . . . . . . . . . . . . . . . . 76
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . . 76
Passenger Sensing System . . . 77
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . 82
Adding Equipment to the Airbag-Equipped Vehicle . . . . . 82
Airbag System Check . . . . . . . . . . 83
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . 83
Child Restraints
Older Children . . . . . . . . . . . . . . . . . 84
Infants and Young Children . . . . 86
Child Restraint Systems . . . . . . . 88
Where to Put the Restraint . . . . . 90
Lower Anchors and Tethers forChildren (LATCH System) . . . . 91 Replacing LATCH System
Parts After a Crash . . . . . . . . . 104
Securing Child Restraints (With the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 104
Securing Child Restraints (In the Center Front Seat) . . . . . . 107
Securing Child Restraints (With the Seat Belt in the Front
Outboard Seat) . . . . . . . . . . . . . 108

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Seats and Restraints 53
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 - 8/27/19
54 Seats and Restraints
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) 091. 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) 091.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Seats and Restraints 55
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 056.
To adjust the lumbar support,
if equipped, see Lumbar Adjustment
0 56.
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.
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 056.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
56 Seats and Restraints
To adjust the lumbar support, see
Lumbar Adjustment056.
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 0255.
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 - 8/27/19
Seats and Restraints 57
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 - 8/27/19
58 Seats and Restraints
Memory Seats
If equipped, memory seats allow two
drivers to save and recall their
unique seat positions for driving the
vehicle, and a shared exit position
for getting out of the vehicle. Other
feature positions may also be
saved, such as power mirrors,
if equipped. Memory positions are
linked to RKE transmitter 1 or 2 for
automatic memory recalls.
Before saving, adjust all available
memory feature positions. Turn the
vehicle on and then press and
release SET; a beep will sound.
Then immediately press and hold 1,2, or
B(Exit) until two beeps
sound. To manually recall these
positions, press and hold 1, 2, or
B
until the saved position is reached.
Follow the instructions under
“Saving Memory Positions.”
The vehicle identifies the current
driver ’s RKE transmitter number
(1–8). See Remote Keyless Entry
(RKE) System Operation (Key
Access) 013 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 16. Only RKE transmitters 1 and 2
can be used for automatic memory
recalls. A Driver Information Center
(DIC) welcome message indicating
the transmitter number may display
for the first few ignition cycles
following a transmitter change. For
Seat Entry Memory to work properly,
save the positions to the memory
button (1 or 2) matching the RKE
transmitter number displayed in the
DIC welcome message. Carry the
linked RKE transmitter when
entering the vehicle. Vehicle Personalization Settings
.
To have the Seat Entry Memory
movement begin when the
vehicle is started, select the
Settings menu, then Vehicle,
then Seating Position, and then
Seat Entry Memory. Select On or
Off. See “Seat Entry Memory”
later in this section.
. To begin Seat Exit Memory
movement when the vehicle is
turned off and the driver door is
opened, or when the vehicle is
turned off with the driver door
already opened, select the
Settings menu, then Vehicle,
then Seating Position, and then
Seat Exit Memory. Select On or
Off. See “Seat Exit Memory”
later in this section.
. See Vehicle Personalization
0 156 for additional setting
information.
Identifying Driver Number
To identify the driver number: 1. Move your RKE transmitter away from the vehicle.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Seats and Restraints 59
2. Start the vehicle with anotherkey or RKE transmitter. The
DIC should display the driver
number for the other RKE
transmitter. Turn the vehicle off
and remove the key or RKE
transmitter from the vehicle.
3. Start the vehicle with the initial key or RKE transmitter. The
DIC should display the driver
number of your RKE
transmitter.
Saving Memory Positions
Read these instructions completely
before saving memory positions.
To save preferred driving positions
1 and 2: 1. Turn the vehicle on or to ACC/ ACCESSORY.
A DIC welcome message may
indicate driver number 1 or 2.
2. Adjust all available memory features to the desired driving
position.
3. Press and release SET; a beep will sound. 4. Immediately press and hold the
1 or 2 memory button matching
the above DIC welcome
message until two beeps
sound.
If too much time passes
between releasing SET and
pressing 1, the memory
position will not be saved and
two beeps will not sound.
Repeat Steps 3 and 4.
1 or 2 corresponds to the driver
number. See “Identifying Driver
Number” previously in this
section.
5. Repeat Steps 1–4 for a second driver using 1 or 2. RKE
transmitters 3–8 will not save
memory positions.
To save the position for
Band
Seat Exit Memory features, repeat
Steps 1–4 using
B. This saves the
position for getting out of the
vehicle.
Save preferred memory feature
positions to both 1 and 2 if you are
the only driver. Manually Recalling Memory
Positions
Press and hold 1, 2, or
Bto recall
the previously saved memory
positions if you are driver 1 or 2
identified in the DIC welcome
message.
To stop Manual Memory recall
movement, release 1, 2, or
Bor
press any of the following controls:
. Power seat
. Memory SET
. Power mirror, with the driver or
passenger side mirror selected
Seat Entry Memory
The vehicle identifies the number of
the current driver ’s RKE transmitter
(1–8). See Remote Keyless Entry
(RKE) System Operation (Key
Access) 013 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 16. If the RKE transmitter is 1 or
2, and Seat Entry Memory is
enabled in vehicle personalization,
the positions saved to the same