Chevrolet 2009 Express Owner's Manual page 28

5. To make the lap part tight, pull up on the
shoulder belt.
It may be necessary to pull stitching on the safety
belt through the latch plate to fully tighten the
lap belt on smaller occupants.
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To unlatch the belt, push the button on the buckle.
The belt should return to its stowed position. Slide the
latch plate up the safety belt webbing when the safety belt
is not in use. The latch plate should rest on the stitching
on the safety belt, near the guide loop on the side wall.
Before a door is closed, be sure the safety belt is out
of the way. If a door is slammed against a safety belt,
damage can occur to both the safety belt and the vehicle.