Pontiac 1997 Grand Prix Owner's Manual page 40

The safety belt locks if
there's a
sudden stop or a crash,
or if you pull the belt very quickly out of the retractor.
Yon can be seriously hurt if your shoulder belt is
too loose. In a crash, you would move forward
too much, which could increase injury. The
shoulder belt should fit against your body.
I
To unlatch the belt, just push the button on the buckle.
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