GMC 2010 Canyon Crew Cab Owner's Manual page 78

Crew Cab
The top tether anchors in a crew cab model are located
on the back wall behind each rear seating position.
Be sure to use an anchor located on the same side of
the vehicle as the seating position where the child
restraint will be placed.
2-50
Extended Cab — Rear Seat
The top tether anchors in an extended cab model are
located on the center of the back wall behind a removable
cover for the rear seating positions. Be sure to use an
anchor located nearest to the seating position where the
child restraint will be placed.