While this page speaks to the unique Ford Smart Trailer Tow connector, this test box should work with any tow vehicle that uses a standard 7-Way Tow Connector.
In their late model pick-up trucks, Ford has added a Smart Trailer Tow Connector. Very little information has been posted about this system, how it work, and what it does.
The sum total of a description of the system is "... the Smart Trailer Tow Connector, which informs you of trailer connectivity issues, burned-out or unlit trailer lights and trailer battery problems." That's it.
To continue, click on this link for complete information http://www.klenger.net/7-way.html