Ford F-150 2010 Owner's Manual page 217

Rear seat tether strap attachment
There are three loops of webbing
just above the back of the rear seat
(along the bottom edge of the rear
window) in the SuperCab and
SuperCrew. These loops are to be
used as both routing loops and
anchor loops for up to three child
safety seat tether straps. For
example, the center loop can be
used as a routing loop for a child
safety seat in the center rear seat
and as an anchoring loop for child seats installed in the outboard rear
seats.
Many tether straps cannot be tightened if the tether strap is hooked to
the loop directly behind the child seat. To provide a tight tether strap:
1. Route the tether strap under the
head restraint and through the loop
directly behind the child seat.
2. Route the tether strap behind the
head restraint supports to a loop
behind an adjacent seating position,
and hook the strap hook onto the
loop. If using the driver's side, pass
the strap behind the shoulder belt
mounting for the center seat.
• Always put the tether strap
through the routing loop. The
head restraint support post will
hold the child seat tightly, but the head restraint post is not strong
enough to hold the child seat during a collision.
Seating and Safety Restraints
217