Ford Mercury Villager 1997 Owner's Manual page 146

Unfastening the auxiliary safety restraint system
Both tongues must be attached to their appropriate buckles
whenever someone is riding in that seating position, and when a
child safety seat has been installed.
When the two-passenger bench seat is removed from the vehicle,
you must detach the single window tongue from the auxiliary
buckle.
Third-row passengers must be very careful when exiting if the
auxiliary restraint system is being used by a second-row passenger.
It is important to step over the seat belt guide and belt
webbing to avoid tripping.
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