GMC 2009 Yukon XL Owner's Manual page 22

Returning the Seat(s) to the Sitting
Position
To return the seat to the sitting position, do the following:
1. Pull the seat down until it latches to the floor. The
seatback cannot be raised if the seat is not latched
to the floor.
CAUTION:
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If either seatback is not locked, it could move
forward in a sudden stop or crash. That could
cause injury to the person sitting there. Always
push and pull on the seatbacks to be sure they
are locked.
2. Lift the seatback and push it rearward. Push and
pull on the seatback to make sure it is locked.
1-16
CAUTION:
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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.
3. Make sure the safety belt in the center seating
position is not caught between the two seats
and is not twisted.