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GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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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.
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GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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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.
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GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
50 Seats and Restraints
To adjust a manual seatback:1. To recline, move the seatback rearward to the desired position, then release the
lever to lock the seatback in place.
Push and pull on the seatback to make
sure it is locked.
2. To return the seatback to the upright position, lift the lever fully without
applying pressure to seatback and the
seatback will return to the upright
position.
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.
Lumbar Adjustment
To adjust the lumbar support, if equipped:
.Press and hold the front or rear of the
control to increase or decrease lumbar
support.
.If equipped, press and hold the top or
bottom of the control to raise or lower
lumbar support.
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GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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Seats and Restraints 51
Uplevel Seat Adjustment
To adjust lumbar support, if equipped:
.Turn the Feature Select (1) to scroll to
lumbar support on the infotainment
display.
.Press Forward (5) or Rearward (3) to
adjust lumbar forward or rearward.
.Press Up (2) or Down (4) to adjust lumbar
up or down.
Bolster Support
To adjust bolster support, if equipped:
Turn the Feature Select (1) to scroll to
bolster support on the infotainment display.
Press Forward (5) or Rearward (3) to adjust
bolster support inward or outward. Upper Shoulder Support
To adjust upper shoulder support,
if equipped:
.Turn the Feature Select (1) to scroll to
upper shoulder support on the
infotainment display.
.Press Forward (5) or Rearward (3) to
adjust shoulder support forward or
rearward.
Massage
If equipped, the vehicle must be on to use
the massage feature.
To activate and adjust massage:
.Turn the Feature Select (1) to scroll to
massage on the infotainment display.
.Press Up (2) or Down (4) to adjust
massage type.
.Press Forward (5) or Rearward (3) to
adjust the intensity.
.To turn massage off or to activate
massage, press the massage On/Off
Control (6).
The massage feature will turn off after
approximately 20 minutes. Press the
massage On/Off Control (6) to restart the
massage feature.
Memory Seats