GMC 2007 Sierra - Manual (Page 41)

To unlatch the belt, push the button on the buckle.
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.
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