Page 17 of 534
Black plate (11,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
In Brief 1-11
.If available, raise or lower the
entire seat by moving the entire
control up or down.
See Power Seat Adjustment on
page 3‑4.
Lumbar Adjustment
Manual Lumbar
If equipped, increase or decrease
manual lumbar support by turning
the knob forward or rearward.
See Lumbar Adjustment on
page 3‑4. Power Lumbar
To adjust the power lumbar support,
if equipped:
.On vehicles with two-way
lumbar, press and hold the top
or bottom of the control to
increase or decrease lumbar
support.
.On vehicles with four-way
lumbar, press and hold the front
or rear of the control to increase
or decrease lumbar support. To
raise or lower the height of the
support, press and hold the top
or bottom of the control.
See Lumbar Adjustment on
page 3‑4.
Reclining Seatbacks
Manual Reclining Seatbacks
To recline a manual seatback:
1. Lift the lever.
Page 19 of 534

Black plate (13,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
In Brief 1-13
Heated and Ventilated
Seats
Heated and Cooled Seat ButtonsShown, Heated Seat Buttons Similar
If available, the buttons are on the
front doors. To operate, the ignition
must be in ON/RUN.
H: If available, press to cool
the seat.
I: Press to heat the
seatback only.
J: Press to heat the seat and
seatback.
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 lights indicate
three for the highest setting and one
for the lowest.
See Heated and Ventilated Front
Seats on page 3‑8.
Head Restraint
Adjustment
Do not drive until the head restraints
for all occupants are installed and
adjusted properly.
To achieve a comfortable seating
position, change the seatback
recline angle as little as necessary
while keeping the seat and the head
restraint height in the proper
position.
See Head Restraints on page 3‑2
and Seat Adjustment on page 3‑3.
Safety Belts
Refer to the following sections for
important information on how to use
safety belts properly.
.Safety Belts on page 3‑11.
.How to Wear Safety Belts
Properly on page 3‑12.
.Lap-Shoulder Belt on page 3‑13.
.Lower Anchors and Tethers for
Children (LATCH System) on
page 3‑45.
Page 64 of 534

Black plate (2,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
3-2 Seats and Restraints
Head Restraints
Front Seats
The front seats have adjustable
head restraints in the outboard
seating positions.
{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.
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.The height of the head restraint can
be adjusted. Pull the head restraint
up to raise it. Try to move the head
restraint to make sure that it is
locked in place.
To lower the head restraint, press
the button, located on the top of the
seatback, and push the restraint
down. Try to move 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 designed to be
removed.
Page 65 of 534

Black plate (3,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Seats and Restraints 3-3
Rear Seats
The rear seat has adjustable
headrests in the outboard seating
positions.
The height of the headrest can be
adjusted. Pull the headrest up to
raise it. To lower the headrest, push
down on the headrest.
Rear outboard headrests are not
designed to be removed.
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 the seat:
1. Lift the bar under the front edgeof the seat cushion to unlock
the seat.
2. Slide the seat to the desired position and release the bar.
3. Try to move the seat back and forth to be sure the seat is
locked in place.
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. Do not use it
as a seating position when the
seatback is folded down.
Page 67 of 534

Black plate (5,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Seats and Restraints 3-5
raise or lower the height of the
support, press and hold the top
or bottom of the control.
Reclining Seatbacks
{WARNING
Sitting in a reclined position when
the vehicle is in motion can be
dangerous. Even when buckled
up, the safety 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
safety 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.
Page 76 of 534

Black plate (14,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
3-14 Seats and Restraints
If the belt stops before it reaches
the buckle, when using the
lap-shoulder belt in a rear center
seating position of a crew-cab,
tilt the latch plate and keep
pulling the safety belt until it can
be buckled.3. Push the latch plate into thebuckle until it clicks.
Pull up on the latch plate to
make sure it is secure. If the belt
is not long enough, see Safety
Belt Extender on page 3‑19.
If the latch plate will not go fully
into the buckle, check if the
correct buckle is being used.
Position the release button on
the buckle so that the safety belt
could be quickly unbuckled if
necessary. 4. If equipped with a shoulder belt
height adjuster, move it to the
height that is right for you. See
“Shoulder Belt Height Adjuster”
later in this section.
5. To make the lap part tight, pull
up on the shoulder belt.
It may be necessary to pull
stitching on the safety belt
through the latch plate to fully
tighten the lap belt on smaller
occupants.
Page 77 of 534
Black plate (15,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Seats and Restraints 3-15
To unlatch the belt, push the button
on the buckle. The belt should
return to its stowed position.
Before a door is closed, be sure the
safety belt is out of the way. If a
door is slammed against a safety
belt, damage can occur to both the
safety belt and the vehicle.
Shoulder Belt Height Adjuster
The vehicle has a shoulder belt
height adjuster for the driver and
right front passenger.
Adjust the height so the shoulder
portion of the belt is on the shoulder
and not falling off of it. The belt
should be close to, but not
contacting, the neck. Improper
shoulder belt height adjustment
could reduce the effectiveness of
the safety belt in a crash. SeeHow
to Wear Safety Belts Properly on
page 3‑12.
Regular and Crew Cab
To move the adjuster down for the
regular and crew cabs, squeeze the
buttons (A) on the sides of the
height adjuster and move the height
adjuster to the desired position.
Page 78 of 534

Black plate (16,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
3-16 Seats and Restraints
Extended Cab
On the extended cab, push down on
the release button (A) and move the
height adjuster to the desired
position.
You can move the adjuster up just
by pushing up on the shoulder belt
guide.
After you move the adjuster to
where you want it, try to move it
down, without squeezing the buttons
for the regular and crew cabs,
or without pushing the release
button for extended cabs, to make
sure it has locked into position.
Safety Belt Pretensioners
This vehicle has safety belt
pretensioners for front outboard
occupants. Although the safety belt
pretensioners cannot be seen, they
are part of the safety belt assembly.
They can help tighten the safety
belts during the early stages of a
moderate to severe frontal, near
frontal, or rear crash if the threshold
conditions for pretensioner
activation are met. And, if your
vehicle has side impact airbags,
safety belt pretensioners can help
tighten the safety belts in a side
crash or a rollover event.
Pretensioners work only once. If the
pretensioners activate in a crash,
they will need to be replaced, and
probably other new parts for the
vehicle's safety belt system. See
Replacing Safety Belt System Parts
after a Crash on page 3‑20.
Rear Safety Belt Comfort
Guides
This vehicle may have rear shoulder
belt comfort guides. If not, they are
available through your dealer. The
guides may provide added safety
belt comfort for older children who
have outgrown booster seats and
for some adults. When installed and
properly adjusted, the comfort guide
positions the belt away from the
neck and head.
Here is how to install a comfort
guide to the shoulder belt:
1. Remove the guide from its storage clip on the interior body.