GMC Yukon Denali 2006 Manual page 18

4. Lower the seat cushion until it latches into position.
Pull up on the seat cushion to make sure it is
locked.
CAUTION:
{
A safety belt that is improperly routed, not
properly attached, or twisted will not provide
the protection needed in a crash. The person
wearing the belt could be seriously injured.
After raising the rear seatback, always check
to be sure that the safety belts are properly
routed and attached, and are not twisted.
5. Make sure that the safety belt buckles on the
driver's side seat are accessible to the outboard and
center occupants and are not under the seat
cushions.
1-12
50/50 Split Bench Seat (Third Row)
If your vehicle has a 50/50 split bench seat, the
seatback(s) can be folded and the entire seat(s) can be
tilted, or removed from the vehicle.
Folding the Seatback(s)
To fold the seatback, do the following:
Pull up on the release
lever labeled 1, located on
the rear of the seatback,
and push the seatback
forward.