Ford Mercury Villager 1997 Owner's Manual page 145

The auxiliary safety restraint system fastened
NOTE: If the three-passenger bench seat is moved up to the
second-row position, the outside passenger (near the
sliding door) only needs to use the double window
tongue and the standard buckle. Because the
third-row seat is wider and is closer to the sliding door,
the single window tongue and the auxiliary buckle
are not necessary.
Seating and Safety Restraints
141