Chevrolet 2009 TrailBlazer Owner's Manual page 52

2. If the child restraint manufacturer recommends that
the top tether be attached, attach and tighten the
top tether to the top tether anchor, if equipped.
Refer to the child restraint instructions and
the following steps:
2.1. Find the top tether anchor.
2.2. Route, attach and tighten the top tether
according to your child restraint instructions
and the following instructions. If your vehicle
has a cargo shade, route the top tether
between the seatback and the cargo shade.
1-48
If the position you are
using does not have a
headrest or head restraint
and you are using a
single tether, route the
tether over the seatback.
See Rear Seat Operation on page 1-11.
If the position you are
using does not have a
headrest or head restraint
and you are using a
dual tether, route the tether
over the seatback.
For vehicles that have a
headrest or head restraint,
fold down the headrest
or head restraint and route
the single tether under
the headrest or head
restraint and in between
the headrest or head
restraint posts.