GMC 2002 Savana Van Owner's Manual page 15

For the remaining rear seats, stow the safety belt
latch plate on the clip at the window trim.
1-8
Replacing the Rear Seats
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 improperly routed, not
properly attached, or twisted 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 properly routed and
attached, and are not twisted.