It is a factory 2 pin connector with a protective cover. (for an accessory I don't have?) The red/blk stripe wire goes to the main terminal of the PDC and the other wire goes under the body toward the back. (along the white line arrow). Any ideas?

 

Tow package?

 

Could be a wire to the rear 7 prong outlet to charge the battery on the RV or trailer when plugged in. Some of the tow packages had 6 prong, 7 prong, and 4 prong connections. Depending on what you have.

If you had a wire package installed without the + going to the trailer then someone could run a wire (usually like a 8 guage) to the back to get as much amperage back there for charging batteries. You need higher voltage to charge the batteries on the tow trailer. This is why you would come right off the battery side of the PDC (to get the 14.2 volts).

 

I have that wire. I think it is some sort of factory (not necessarily dealer) test port.

IndyDurango

 

It's the power supply for the rear of the vehicle so you can hang your "Ford Sucks" neon sign on the back window.

 

I can aggree with that!

 

Mystery solved.
I thought the cap was to protect an unused connector but under that cap is a 20amp fuse. Just above the white arrow in the picture is a light blue wire that goes into the black tubing around the wires. Then the red and LB wires go along the frame rail and connect into the rear lights and trailer connector. The LB wire also goes through the firewall and is coiled and taped under the steering column for...................
a trailer brake.

 

Sounds like I nailed it.