GMC SIERRA CK2 1999 Owner's Manual page 27

Q:
What's wrong with this?
A:
The belt is twisted across the body.
CAUTION:
You can be seriously injured by a twisted belt.
In a crash, you wouldn't have the full width of
the belt to spread impact forces. If a belt is
twisted, make it straight so it can work properly,
or ask your dealer to fix it.
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