Chevrolet 1999 Express Van Owner's Manual page 14

For the remaining rear seats, stow the safety belt
latch plate on the clip at the window trim.
1-8
Replacing the Rear Seat
CAUTION:
A seat that isn't locked into place properly can
move around in a collision or sudden stop. People
in the vehicle could be injured. Be sure to lock
the seat into place properly when installing it.
CAUTION:
A safety belt that is twisted or not properly
attached won't provide the protection needed in a
crash. The person wearing the belt could be
seriously injured. After installing the seat, always
check to be sure that the safety belts are not
twisted and are properly attached.
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