GMC Sierra Owner's Manual page 95

94 Seats and Restraints
Do not secure a child seat in a position
without a top tether anchor if a national or
local law requires that the top tether be
anchored, or if the instructions that come
with the child restraint say that the top
tether must be anchored.
In Canada, the law requires that
forward-facing child restraints have a top
tether, and that the tether be attached.
When using the lap-shoulder belt to secure
the child restraint in this position, follow the
instructions that came with the child
restraint and the following instructions:
1. Move the seat as far back as it will go
before securing the forward-facing child
restraint. Move the seat upward or the
seatback to an upright position,
if needed, to get a tight installation of
the child restraint.
When the passenger sensing system has
turned off the front outboard passenger
frontal airbag, the OFF indicator on the
passenger airbag status indicator should
light and stay lit when you start the
vehicle. See Passenger Airbag Status
Indicator 0 116.
2. Put the child restraint on the seat.
3. Pick up the latch plate, and run the lap
and shoulder portions of the vehicle seat
belt through or around the child
restraint. The child restraint instructions
will show you how.
Tilt the latch plate to adjust the belt if
needed.
4. Push the latch plate into the buckle until
it clicks.
Position the release button on the
buckle, away from the child restraint, so
that the seat belt could be quickly
unbuckled if necessary.