Hummer 2006 H3 Owner's Manual page 48

5. If the child restraint is forward-facing, attach and
tighten the top tether to the top tether anchor.
Refer to the child restraint instructions and
the following steps:
5.1. Find the top tether anchor.
5.2. Route and tighten the top tether according to
your child restraint instructions and the
following instructions:
1-42
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.
6. Push and pull the child restraint in different
directions to be sure it is secure.
If the position you are
using has a fixed head
restraint and you are
using a single tether,
route the tether over the
head restraint.
If the position you are
using has a fixed or
adjustable head restraint
and you are using a
dual tether, route the tether
around the head restraint.