GMC Yukon XL Denali Owner's Manual page 76

3-22 Seats and Restraints
Rear Safety Belt Comfort
Guides
This vehicle may have rear shoulder
belt comfort guides. If not, they are
available through your dealer. The
guides may provide added safety
belt comfort for older children who
have outgrown booster seats and
for some adults. When installed and
properly adjusted, the comfort guide
positions the belt away from the
neck and head.
There is one guide, if equipped, for
each outside passenger position in
the second row seat.
Here is how to install a comfort
guide to the safety 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.