2003 GMC Envoy Owner's Manual - Page 48

Anchor the top strap to one of the following anchor points. Be sure to use an anchor point located on the same side of the vehicle as the seating position where the child restraint will be placed. Raise the head restraint and route the top strap under it. See Head Resfraints on page 1-5. Once you have the top strap anchored, you'll be ready to secure the child restraint itself. Tighten the top strap when and as the child restraint manufacturer's instructions say. Top Strap Anchor Location Envoy Anchor brackets for the rear seat positions are located on the floor in the cargo area of your vehicle (Envoy only). Do not use the rear tie-down brackets near the liftgate for top strap tethers. 1-41