Buick 2009 Enclave Owner's Manual page 50

2. If the child restraint manufacturer recommends that
the top tether be attached, attach and tighten the
top tether to the top tether anchor, if equipped.
Refer to the child restraint instructions and
the following steps:
2.1. Find the top tether anchor.
2.2. Open the top tether anchor cover to expose
the anchor.
2.3. Route, attach, and tighten the top tether
according to your child restraint instructions
and the following instructions:
1-46
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 a fixed headrest
or head restraint and
you are using a single
tether, route the tether over
the headrest or head
restraint.