GMC Sierra 2018 Owner's Manual page 115

114 Seats and Restraints
5. Pull the shoulder belt all the
way out of the retractor to set
the lock. When the retractor
lock is set, the belt can be
tightened but not pulled out of
the retractor.
6. To tighten the belt, push down
on the child restraint, pull the
shoulder portion of the belt to
tighten the lap portion of the
belt, and feed the shoulder belt
back into the retractor. When
installing a forward-facing child
restraint, it may be helpful to
use your knee to push down on
the child restraint as you
tighten the belt.
Try to pull the belt out of the
retractor to make sure the
retractor is locked. If the
retractor is not locked, repeat
Steps 5 and 6.
7. If the vehicle does not have a
rear seat and the child restraint
manufacturer recommends
using a top tether anchor,
attach the top tether to the top
tether anchor. Refer to the
instructions that came with the
child restraint and to Lower
Anchors and Tethers for
Children (LATCH System) 0 96.
8. Before placing a child in the
child restraint, make sure it is
securely held in place. To
check, grasp the child restraint
at the seat belt path and
attempt to move it side to side
and back and forth. When the
child restraint is properly
installed, there should be no
more than 2.5 cm (1 in) of
movement.
If the vehicle is equipped with a
passenger sensing system, and
when the passenger sensing system
has turned off the front outboard
passenger frontal airbag, the off
indicator in the passenger airbag
status indicator will come on and
stay on when the vehicle is started.