GMC 2011 Sierra Denali Owner's Manual page 106

3-52 Seats and Restraints
Your child restraint may have a
single tether (A) or a dual tether (C).
Either will have a single
attachment (B) to secure the top
tether to the anchor.
Some child restraints that have a
top tether are designed for use with
or without the top tether being
attached. Others require the top
tether always to be attached. In
Canada, the law requires that
forward-facing child restraints have
a top tether, and that the tether be
attached. Be sure to read and follow
the instructions for your child
restraint.
Lower Anchor and Top Tether
Anchor Locations
Rear Seat
(Top Tether Anchor): Seating
positions with top tether anchors.
(Lower Anchor): Seating
positions with two lower anchors.
The rear outboard seating positions
have exposed metal lower anchors
located in the crease between the
seatback and the seat cushion.
The top tether anchors are the loops
located near the top of the seatback
for each rear seating position.
These loops will be used to route
the top tether through, as well as, to
secure the top tether in the vehicle.
Be sure to use an anchor (loop)
located on the same side of the
vehicle as the seating position
where the child restraint will be
placed.