GMC 2009 Sierra - Manual (Page 31)

Rear Safety Belt Comfort Guides
Rear shoulder belt comfort guides may provide added
safety belt comfort for older children who have outgrown
booster seats and for some adults. When installed on a
shoulder belt, the comfort guide positions the belt away
from the neck and head.
There is one guide for each outboard passenger position
in the rear seat. Here is how to install a comfort guide to
the shoulder belt:
1. Remove the guide from its storage clip on the
interior body.
2. 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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