2013 F350 FX4 Crew-cab 6.7.

The truck today when pulling home our 5th wheels would buzz then give the "Trailer Disconnected" message on the screen. I would still have running lights, brake lights and turn signals while the "Trailer Disconnected" would be present.

Further down the road I would get the "Trailer Connected" message, and then a bit later the "Trailer Disconnected" message. This kept happening for the entire trip home. Sometimes it would happen when we hit a bump in the road, other times it just occurred.

I did notice that when it was reading "Trailer Disconnected" there was no power feed to the trailer per the screen.

After getting home I backed the trailer in the driveway and it then read "Connected". I jiggled the plug and it went to "Disconnected"

I used a 12V test light at the trailer plug and have all lights. However, is I touch the brake power feed lead and someone steps on the brakes I get no power to the test light. Which in my little mind I should if it were working properly.

Any suggestions?

I will try hooking up the trailer cord to my other trailer to check to make sure that it is either on the truck end or the trailer end of the problem.

When testing the plug with a light tester do I need to use the ground point on the trailer receptacle to complete a circuit?

 

OK, I plugged another trailer into my truck with the same results. All lights work, but I still get a "Trailer Disconnected" screen message.

 

The plug you wiggled, I would just take it all apart and visually check everything and tighten/check all the connections. You could also take the wires out of the plug, and take pliers and tug on the copper ends on all the wires. They should resist the tugging and not pull out. If you have one that pulls out, then that's your problem.

 

My son brought over his 2015 F150 and we hooked the trailer up to it. Everything worked as it should, so now I am confident that the issue is the truck.

Tomorrow I will pull the connector plugs under the truck as well as the trailer plugs, clean them apply a fresh coating a dielectric grease and give it a try. It was a long day of driving in the rain today, maybe part of the problem could have been moisture infiltration at the connection points.

 

Done, fixed, did it myself.

Crawled under the truck and pulled the connectors apart, including the Ford OEM connectors and the jumper harness where a in the bed plug was installed. Cleaned the contacts and gave a fresh coat of dielectric grease, reassembled everything and it works just fine. I'm guessing that I got some moisture in the contacts where there was not any grease on the contacts and it triggered an error/short/dead loop.