GMC Sierra Denali 2017 Owner's Manual page 64

To unlatch the belt, push the button
on the buckle. The belt should
return to its stowed position.
Always stow the safety belt slowly.
If the safety belt webbing returns
quickly to the stowed position, the
retractor may lock and cannot be
pulled out. If this happens, pull the
safety belt straight out firmly to
unlock the webbing, and then
release it. If the webbing is still
locked in the retractor, see your
dealer.
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
front outboard 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. See How
to Wear Safety Belts Properly 0 60.
Push down on the release button to
move the height adjuster to the
desired position.
Move the adjuster up by pushing up
on the shoulder belt guide.
After the adjuster is set to the
desired position, try to move it down
without pushing the release button
to make sure it has locked into
position.
Seats and Restraints
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. If the vehicle has rollover
roof-rail airbags, safety belt
pretensioners can help tighten the
safety belts in a rollover event.
Pretensioners work only once. If the
pretensioners activate in a crash,
they will need to be replaced, and
the vehicle's safety belt system will
probably need other new parts. See
Replacing Safety Belt System Parts
after a Crash 0 66.
Do not sit on the outboard safety
belt while entering or exiting the
vehicle or at any time while sitting in
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