GMC 2004 Yukon XL Owner's Manual page 21

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.
To reinstall the 50/50 split bench, do the following:
1. While holding the rear of the seat up, slide the front
wheels into the slots on the floor. The front latches
should lock into place. If the latches do not lock,
try tilting the rear of the seats upwards.
2. Once the latches are engaged, let the seat drop
into place. Release the lever labeled 1 to return
the seat to its upright position.
3. Push and pull on the seat to make sure it is locked
into place. The seatback cannot be raised to the
upright position unless the seat is secured to
the floor.
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