2021 GMC SIERRA Owner's Manual

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
48 Seats and Restraints
Some vehicles are equipped with a feature
that activates a vibrating pulse alert in the
driver seat to help the driver avoid crashes.
SeeDriver Assistance Systems 0265.
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.
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.
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.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Seats and Restraints 49
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.
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

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
50 Seats and Restraints
hold 1, 2, orBuntil 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) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013. 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.
.SeeVehicle Personalization 0131 for
additional setting information.
Identifying Driver Number
To identify the driver number: 1. Move your RKE transmitter away from the vehicle.
2. Start the vehicle with another key 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.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Seats and Restraints 51
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
Manual Memory recall movement for 1, 2,
or
Bbuttons may be initiated and may
complete to the saved memory position if
the vehicle is in or out of P (Park).
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) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013. If the RKE
transmitter is 1 or 2, and Seat Entry Memory
is enabled in vehicle personalization, the positions saved to the same 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
0 131.
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, orB
.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 0131.
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, orB
.Power mirror, with the driver or
passenger side mirror selected

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
52 Seats and Restraints
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 overheat. An
overheated seat heater may cause a burn
or may damage the seat.Heated and Ventilated Seat Buttons Shown,Heated Seat Buttons Similar
If equipped, the buttons are on the center
stack. To operate, the engine must be
running.
Press
Ior+to heat the driver or
passenger seatback only.
Press
Jorzto heat the driver or
passenger seat cushion and seatback.
Press
Cor{to ventilate the driver or
passenger seat.
The indicator light on the button comes on
when this feature is on. Press the button once for the highest
setting. With each press of the button, the
seat will change to the next lower setting,
and then to the off setting. The indicator
lights next to the buttons indicate three for
the highest setting and one for the lowest.
If the heated seats are on high for an
extended time, their level may automatically
be lowered.
Auto Heated Seats
When the vehicle is on, this feature will
automatically activate the heated seats at
the level required by the vehicle’s interior
temperature. The active high, medium, low,
or off heated seat level will be indicated by
the manual heated seat buttons on the
center stack. Use the manual heated seat
buttons on the center stack to turn auto
heated seats off. If the passenger seat is
unoccupied, the auto heated seats feature
will not activate that seat. The auto heated
seats feature can be programmed to always
be enabled when the vehicle is on. See
Vehicle Personalization
0131.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Seats and Restraints 53
Remote Start Heated and Ventilated Seats
If equipped, the heated seats will turn on
automatically during a remote start if it is
cold outside and the ventilated seats will
turn on automatically if it is hot outside.
If equipped, the heated steering wheel will
turn on automatically during a remote start
if it is cold outside. The heated and
ventilated seat indicators and heated
steering wheel indicator may not come on
during this operation.
The heated and ventilated seats and heated
steering wheel may cancel when the vehicle
is started. These features can be manually
selected after the ignition is turned on.
The temperature performance of an
unoccupied seat may be reduced. This is
normal.
The heated or ventilated seats will not turn
on during a remote start unless they are
enabled in vehicle personalization. See
Remote Vehicle Start020 and
Vehicle Personalization 0131.Rear Seats
Rear Seat Reminder
If equipped, the message REAR SEAT
REMINDER LOOK IN REAR SEAT displays
under certain conditions indicating there
may be an item or passenger in the rear
seat. Check before exiting the vehicle.
This feature will activate when a second row
door is opened while the vehicle is on or up
to 10 minutes before the vehicle is turned
on. There will be an alert when the vehicle
is turned off. The alert does not directly
detect objects in the rear seat; instead,
under certain conditions, it detects when a
rear door is opened and closed, indicating
that there may be something in the
rear seat.
The feature is active only once each time
the vehicle is turned on and off, and will
require reactivation by opening and closing
the second row doors. There may be an
alert even when there is nothing in the rear
seat; for example, if a child entered the
vehicle through the rear door and left the
vehicle without the vehicle being shut off.
The feature can be turned on or off. See
Vehicle Personalization 0131.
Folding the Rear Seat Cushion
Either side of the rear seat cushion can be
folded up for added cargo space.
Caution
Folding a rear seat with the seat belts
still fastened may cause damage to the
seat or the seat belts. Always unbuckle
the seat belts and return them to their
normal stowed position before folding a
rear seat.
Make sure that nothing is on the seat
cushion.
To fold the seat, slowly pull the seat
cushion up.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
54 Seats and Restraints
To return the seat to the normal seating
position, slowly pull the seat cushion down.
{Warning
A seat belt that is improperly routed, not
properly attached, or twisted will not
provide the protection needed in a crash.
The person wearing the belt could be
seriously injured. After raising the rear
seatback, always check to be sure that
the seat belts are properly routed and
attached, and are not twisted.
Heated Rear Seats
{Warning
If you cannot feel temperature change or
pain to the skin, the seat heater may
cause burns. See the Warning under
Heated and Ventilated Front Seats052.
If available, the buttons are on the rear of
the center console. To operate, the engine
must be running.
Press
MorLto heat the left or right
outboard seat cushion. An indicator on the
climate control display appears when this
feature is on.
This feature turns on at the highest setting.
With each press of the button, the heated
seat changes to the next lower setting, and
then the off setting. Three lights indicate
the highest setting, and one light indicates
the lowest. If the heated seats are on high,
the level may automatically be lowered
after approximately 30 minutes.
Seat Belts
This section describes how to use seat belts
properly, and some things not to do.
{Warning
Do not let anyone ride where a seat belt
cannot be worn properly. In a crash,
if you or your passenger(s) are not
wearing seat belts, injuries can be much
worse than if you are wearing seat belts.
You can be seriously injured or killed by
hitting things inside the vehicle harder or
by being ejected from the vehicle. In
addition, anyone who is not buckled up
can strike other passengers in the vehicle.
It is extremely dangerous to ride in a
cargo area, inside or outside of a vehicle.
In a collision, passengers riding in these
areas are more likely to be seriously
injured or killed. Do not allow passengers
to ride in any area of the vehicle that is
not equipped with seats and seat belts.
Always wear a seat belt, and check that
all passenger(s) are restrained
properly too.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Seats and Restraints 55
This vehicle has indicators as a reminder to
buckle the seat belts. SeeSeat Belt
Reminders 0113.
Why Seat Belts Work
When riding in a vehicle, you travel as fast
as the vehicle does. If the vehicle stops
suddenly, you keep going until something
stops you. It could be the windshield, the
instrument panel, or the seat belts!
When you wear a seat belt, you and the
vehicle slow down together. There is more
time to stop because you stop over a longer
distance and, when worn properly, your
strongest bones take the forces from the
seat belts. That is why wearing seat belts
makes such good sense.
Questions and Answers About Seat Belts
Q: Will I be trapped in the vehicle after a
crash if I am wearing a seat belt?
A: You could be— whether you are
wearing a seat belt or not. Your chance
of being conscious during and after a
crash, so you canunbuckle and get out,
is much greater if you are belted.
Q: If my vehicle has airbags, why should I have to wear seat belts?
A: Airbags are supplemental systems only.
They work withseat belts —not instead
of them. Whether or not an airbag is
provided, all occupants still have to
buckle up to get the most protection.
Also, in nearly all states and in all
Canadian provinces, the law requires
wearing seat belts.
How to Wear Seat Belts Properly
Follow these rules for everyone's protection.
There are additional things to know about
seat belts and children, including smaller
children and infants. If a child will be riding in the vehicle, see
Older Children071 or
Infants and Young Children 072. Review and
follow the rules for children in addition to
the following rules.
It is very important for all occupants to
buckle up. Statistics show that unbelted
people are hurt more often in crashes than
those who are wearing seat belts.
There are important things to know about
wearing a seat belt properly.
.Sit up straight and always keep your feet
on the floor in front of you (if possible).
.Always use the correct buckle for your
seating position.