GMC Yukon Denalid Owner's Manual page 78

Second Row Seat — 60/40
For models with 60/40 second row seating, the top
tether anchors are located at the bottom rear of
the seat cushion for each seating position in
the second row. 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.
78
Third Row Seat — Two or Three Passenger
For vehicles with a two passenger third row seat,
there is one top tether anchor located at the
bottom rear of the seat cushion that can be used
for the rear driver side seating position in the
third row. Never install two top tethers using the
same top tether anchor.
For vehicles with a three passenger third row seat,
there is one top tether anchor located at the
bottom rear of the seat cushion that can be used
for either the third row center or driver side
seating position. Never install two top tethers using
the same top tether anchor.