Ford Mercury Villager 1997 Owner's Manual page 240

Trailer Tow Module (If equipped)
The trailer tow module on your vehicle (if equipped) allows
turn/stop lamp control on a trailer being towed by your vehicle.
The trailer tow package includes:
trailer tow module which is protected by the vehicle stop
lamp fuse
one SAE J1239 specified connector
one extension harness within the rear bumper
heavy duty battery
full size spare
If you need further assistance in wiring a trailer to your vehicle,
contact your Ford or Lincoln-Mercury dealer.
Driving While You Tow
Be especially careful when driving while you tow a trailer. Never
drive faster than 45 mph (70 km/h) when you tow in hilly
country on hot days. Also, anticipate stops so that you can brake
gradually.
If you use the speed control while you are towing on very long,
steep grades, the speed control may shut off automatically.
This is caused by the decrease of vehicle speed 5 mph (8 km/h)
lower than set speed.
When descending a steep grade with a trailer, operate in Drive
rather than Overdrive. If additional braking is needed, shift into 2
(Second) or 1 (First) gear.
Servicing Your Vehicle If You Tow
If you tow a trailer for a long distance, your vehicle will need to
be serviced more frequently than usual. See the Maintenance
Schedule booklet in the Owner's portfolio.
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