GMC 2016 Yukon XL Denali Owner's Manual page 99

98 Seats and Restraints
1.3. Attach and tighten the
lower attachments on the
child restraint to the lower
anchors.
2. If the child restraint
manufacturer recommends that
the top tether be attached,
attach and tighten the top
tether to the top tether anchor.
Refer to the child restraint
instructions and the following
steps:
2.1. Find the top tether anchor.
For the third row seat,
move the flipper panel
rearward to access the top
tether anchors.
2.2. Route, attach, and tighten
the top tether according to
your child restraint
instructions and the
following instructions:
If the position you are
using does not have a
head restraint and you are
using a single tether, route
the tether over the
seatback.
If the position you are
using does not have a
head restraint and you are
using a dual tether, route
the tether over the
seatback.
If the position you are
using has an adjustable
head restraint and you are
using a single tether, raise
the head restraint and
route the tether under the
head restraint and in
between the head
restraint posts.