My apologies if this has been discussed in another thread, but I didn't feel like wading through 4900 topics. LOL.

Dashboard suddenly is not recognizing that the trailer is connected. Owners manual is of little help, except to mention that this may be an issue with aftermarket TBCs. All lights are functioning on the trailer, but the trailer appears to have no brakes when I manually squeeze the factory installed TBC.

I've inspected the wiring harness at the hitch. Nothing appears loose, corroded or disconnected.

One thing, my trailer has been in need of adjusting the brakes for some time. I've got the TBC gain set at a 9 before it starts to properly brake. So I'm wondering if the trailer isn't sending a proper signal back to the truck regarding brakes, then maybe that could be causing the issue?

It's apparent from my research that this message display would be better if it said "No Brake Signal". Because obviously the dang thing is connected and all the lights work. It's the brake that is creating the message. So saying "Trailer Disconnected" is ambiguous and misleading. It's like getting a signal that says, "FLUID LOW". What fluid, Mr. Ford?

Anyway, thanks in advance for the help. This forum is always super-duty helpful :-)

Chris

 

I had the exact same issue with my 16 F250. Pulled over at Donner Summit, after a rest, pulled onto freeway and got the trailer disconected light. No brakes, but the trailer lights were working. Short story, turned out to be the ground wires on the trailer. The manufacturer had 5 12 gage wires crammed into a single wire nut, two wires that were twisted together had fallen out of the nut. Fixed it by splitting them and using a jumper with two appropriate wire nuts. So I would open the junction box on the trailer and check the ground. Should be the white wire, as most manufactures use white for ground. Good luck!

 

Good stuff, Old Turnkey. I'll check it.

One more variable - the trailer happens to be a 2005 Airstream. And I share that Airstream with my brother, who has the same exact truck. He told me that on the last trip (we swap off on camping trips pretty regularly) that he had no issues.

But it's certainly possible that this is a brand new issue. I'm going to have him come over and hook up to see if he's now getting the same signal. That would also tell me if the problem is on the trailer or the truck.

 

Just take a jumper cable and attach it to your trailer frame and the truck frame. that should establish a ground. Does it end the problem? My guess is given how far you have your controller dialed up, you have a connection issue.

 

I believe it monitors all lights for ground and if one doesn't make the circuit it can give you the trailer disconnected message. That's why your lights still work and you get the message. I have a '15 and I tow both cargo, and boat. The boat has surge brakes but if I do not get the flat trailer connector seated properly I get the trailer disconnect message even when the tail lights are working. I know this due to towing the boat in the dark, getting trailer disconnected message and can still see the side marker lights on the trailer working. I also get trailer turn signal messages if the turn signals aren't working.

I thought it monitored electric brakes but that thought went out the window when I got the same messages pulling the boat without electric brakes.

 

It looks for a completed brake circuit. The trailer lights should work regardless.