Chevrolet TrailBlazer 2007 Owner's Manual page 39

2. Slide the guide under and past the belt. The
elastic cord must be under the belt. Then,
place the guide over the belt and insert
the two edges of the belt into the slots
of the guide.
3. Be sure that the belt is not twisted and it lies
flat. The elastic cord must be under the belt
and the guide on top.
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