GMC 2007 Yukon XL Owner's Manual page 50

Q:
What is wrong with this?
A:
The belt is twisted across the body.
50
CAUTION:
{
You can be seriously injured by a twisted
belt. In a crash, you would not 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.