Cadillac 2008 SRX Owner's Manual page 52

2.3. Route, attach and tighten the top tether
according to your child restraint instructions
and the following instructions:
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.
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.
3. Push and pull the child restraint in different
directions to be sure it is secure.
If the position you are using
has an adjustable headrest
or head restraint and you
are using a dual tether,
route the tether under
the head restraint and
in between the head
restraint posts.
If the position you are using
has an adjustable headrest
or head restraint and you
are using a single tether,
route the tether under the
headrest or head restraint
and in between the
headrest or head
restraint posts.