Chevrolet 2012 Sonic Owner's Manual page 90

3-44 Seats and Restraints
2.4. Route and tighten the top
tether according to your
child restraint instructions
and the following
instructions:
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.
If the position you
are using has an
adjustable headrest
or head restraint and
you are using a
single tether, raise
the headrest or head
restraint and route
the tether under the
headrest or head
restraint and in
between the
headrest or head
restraint posts.