GMC Yukon XL Denali 2005 Owner's Manual page 51

There is one guide for each passenger position in the
rear seats. Here is how to install a comfort guide
and use the safety belt:
Second Row Seat
1. For the second row, remove the guide from its
storage clip on the trim panel near the side of
the seatback or from the side of the center seat.
Third Row Seat
For the third row, remove the guide from its storage
clip on the side of the seatback.
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