Chevrolet 2006 Avalanche Owner's Manual page 52

1.3. Route the top tether according to your child
restraint instructions and the following
instructions:
1-46
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 dual tether,
route the tether around the
head restraint.
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.
1.4. Attach the top tether attachment to the top
tether anchor.