Buick 2009 Lucerne - Manual (Page 58)

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 a fixed headrest
or head restraint and
you are using a single
tether, route the tether over
the headrest or head
restraint.
If the position you are
using has a fixed headrest
or head restraint and
you are using a dual tether,
route the tether around
the headrest or head
restraint.
3. Push and pull the child restraint in different
directions to be sure it is secure.
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