GMC C series 2002 Owner's Manual page 27

Bench (A) Suspension (B)
To unlatch the belt, just push the button on the
buckle. The belt should go back out of the way.
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For a suspension type seat, if the belt is pulled out
all the way so that it locks, press down on the button
on the retractor cover to make it retract.
Before you close the door, be sure the belt is out of the
way. If you slam the door on it, you can damage both
the belt and your vehicle.
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