Pontiac Wave 2009 Owner's Manual page 54

2.5. Route and tighten the top tether according to
your child restraint instructions and the
following instructions:
1-50
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 a headrest or head
restraint and you are using
a dual tether, route the
tether under the headrest
or head restraint and in
between the headrest or
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.