2004 GMC Yukon Owner's Manual - Page 62

If you have an adjustable head restraint, route the top strap under it. Top Strap Anchor Location Yukon/Yukon XL models with rear seats: A child restraint with a top strap should only be used in the second or third row. Don't use a child restraint with a top strap in the front seat because there's no place to anchor the top strap. Do not secure a child restraint with a top strap in the right front passenger's position or in the third row driver's side position if a national or local law requires that the top strap be anchored, or if the instructions that come with the child restraint say that the top strap must be anchored. There is no place to anchor the top strap in these positions. An anchor loop bracket for a top strap is located at the bottom rear of the seat cushion for each seating position in the second row, and for the center seating position in the third row. {CAUTION: Each top tether bracket is designed to anchor only one child restraint. Attaching more than one child restraint to a single bracket could cause the anchor to come loose or even break during a crash. A child or others could be injured if this happens. To help prevent injury to people and damage to your vehicle, attach only one child restraint per bracket. Once you have the top strap anchored, you will be ready to secure the child restraint itself. Tighten the top strap when and as the child restraint manufacturer's instructions say. 1-56