If you have the tow package it should just hook up at the rear tow plug. Check owner's manual. If you don't have one copy and paste link below; www.fleet.ford.com/maintenance/owners_manuals
I would check the running lights for one with a short. I had the same sort of thing with my trailer and I spent way to much time troubleshooting the brake and signal wires. Turns out a running light bulb connector was grounding out on the trailer and messing it all up.
Tail lights and brake lights fuse.
Fuse is blown light connector is unplugged ground wire on trailer disconnected
Take a light tester and check the pins at the truck side trailer plug. With the truck set for running lights check for power at the pins. If there is power then there is a loose or bad wire on the trailer side. If there is no power then there is a power problem on the truck side.
Generally, that fuse is located under the hood on the drivers side in front of the firewall. Some guys call it the "ice cube tray", it houses the relays and other fuses. Open the cover and look at the diagram, there should be 3 or 4 fuses labeled "trlr" with LT(left turn) RT and MKR(marker lights or running lights) typically a 30 amp maxi fuse, its a big green thing.
Trailer Lights Not Working ProperlyWithout being able to physically see and troubleshoot the defective trailer light wiring system [from the attachment to the vehicle wiring harness (s) all the way to each of the trailer lamps [light bulbs], one can only speculate.I suspect that the cause for part of the lamp filaments working properly while some don't is the result of connecting some wires to the wrong wires.
Yes, just like you would anywhere else.
The running lights have a bad ground.
I would first check the grounding between the truck and the trailer. If the ground is good then bulbs would be the next thing to check.
You need to specify what type of connector. Most likely, you'll be using a seven blade connector, although six pin, five pin, and four pin connectors are also a possibility. The latter two would only be used if your trailer was not equipped with trailer brakes.
Hey E==The running lights have a module which may be bad. Good luckJoe
Try the tractor with a different trailer, the pig tail is most likely not connecting properly.