GMC 2002 Yukon XL Owner's Manual page 72

Tahoe/Yukon models: A child restraint with a top strap
should only be used in the second row. Don't use a child
restraint with a top strap in the right front passenger's
position or in the third row, because there's no place to
anchor the top strap.
An anchor loop bracket for a top strap is located at the
bottom rear of the seat cushion for the center seating
position in the third row.
Suburban/Yukon XL Third Row Seat
Tahoe/Yukon Second Row Seat
1-65