FORD 2003 Thunderbird v.1 - Manual (Page 98)

Attaching child safety seats with tether straps
Most new forward-facing child safety seats include a tether strap which
goes over the back of the seat and hooks to an anchoring point. Tether
straps are available as an accessory for many older safety seats. Contact
the manufacturer of your child seat for information about ordering a
tether strap.
The tether strap anchors in your
vehicle are in the following positions
(shown from top view):
Attach the tether strap only to the appropriate tether anchor as
shown. The tether strap may not work properly if attached
somewhere other than the correct tether anchor.
1. Position the child safety seat on the passenger seat cushion.
2. Locate the tether anchor at the
bottom back of the passenger seat.
Seating and Safety Restraints
98