GMC 2007 Yukon XL Owner's Manual page 57

There is one guide for each outside passenger
position in the second row seat and the third row,
if your vehicle has one. Here is how to install a
comfort guide and use the safety belt:
Second Row
1. For the second row, remove the guide from its
storage clip on the interior body.
Third Row
If your vehicle has a third row, remove the
guide from its storage pocket on the side of
the seat.
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