I've been trying to research this issue and answers have been all over the place. Wondering if there had been a definitive answer.
I have a 2018 XLT. I have towed my camper all summer on a regular ball and reciever with no issue. We are going on a week long camping trip soon so I installed a weight distribution hitch this weekend. Now when I tow the camper I'm constantly getting the trailer disconnected warning. I'm assuming it is all to do with the factory brake controller. Lights all work and don't even flicker. Brake gain pops up after I get the warning also.
I have seen answers to this issue all over but mostly with older models. Some were a updated TSB about reprogramming but only up to 2015. Seen others about using a aftermarket plug extension. Another on adding a load resister. Others changing truck setting to electric over hydraulic. And a million other attempts at fixes.
I'm assuming there has to be plenty of people with this issue. Has Ford figured out anything? I had the brake controller installed in June. I would think it would have the latest software.

 

I had this problem and it was a trailer grounding issue, not the truck. Anecdotal of course, but in my experience it is actually almost always the trailer wiring, and almost always the ground.

 

OP doesn't say what he tried. Did you setup the trailer properly, following the manual's instructions, including setting the brakes?

 

I have towed the camper all summer with no issue until I installed the weight distribution hitch. Trailer brakes work fine. I highly doubt the trailer wiring is at fault. It's a 2021 camper and like I said I can throw a regular ball and reciever on and the issue is not there.

 

So you are using the same plug on the truck (7 pin) with both hitches? Then the brake controller should be no issue, because the brake controller was being used with the same connection (7 pin) without the WDH.

If so, then the issue is likely trailer ground, and is likely caused by the connection between the vehicle and the trailer. If all the connection points (hitch to vehicle, ball to trailer) seems to have good, non-painted contact, then try running a ground wire from the truck to the trailer, and do a drive around locally and see what happens.

 

Yes everything is the same except the hitch and new ball. Connector is tight with no wiggle. I'm assuming the BC is way more sensitive than the lights. Lights don't even flicker. And I would lose my rear camera on the camper seeing it is powered through the running lights. The hitch is painted. Maybe I'll have to take it apart and sand down the matting surfaces a bit.

 

Pin number 1 is your ground. No need to rely on metal to metal contact unless the pin connection is bad. Double check the wiring near the spring bar brackets that were installed when you added the WDH. Perhaps they got pinched there.

 

Just because the camper is 2021 means nothing. QC in the rv industry is a joke.
I too believe it is a ground issue, and the painted ball should NOT be a ground source. As others suggest, simply grab your jumper cables, get at a good ground spot under your truck, then to the trailer, simple easy test. A wdh verses a traditional hitch has NO logical bearing on whether the lights work properly, it seems it is simply a coincidence.

 

I get that but it's kinda odd that I've used it almost every weekend since June without issue and as soon as I threw a WDH on this happened.

 

Mine also did that with my new trailer so I just cleaned the outlet with electrical cleaner and put some dielectric grease on the prongs and haven't had a problem since.