Trailer Disconnected / Trailer Fault Message on Dash

[MPTonyT]

So I have searched and read extensively on this subject. I'm trying to cure the issue in my personal truck. Let me start by telling you the symptoms and what I have tried and see if anyone has any other things to try.

Hooked up my family's 24ft Fleetwood Prowler Camper (bumper pull) to pull it back to the house to prep it for a camping trip we are about to go on. After hooking it up I checked the lights and the trailer brakes and all seemed fine. Get out on the road and for the first 15 miles or so the brakes work fine. I thought this was awesome since I have been fighting this issue every time i tow this thing. I get on the interstate and when cruising along (not hitting any bumps) it will show "Trailer Disconnected" on the dash and my gain will flash, then a few seconds later it will reset. It seems to do this every mile or 1/2 mile. It was about a 40 mile trip and I swear it did it 100 times. I reach down to manually apply the brakes and its like it tries to but then shows Trailer Disconnected sometimes followed by Trailer Fault. So when it is throwing its fit the trailer brakes will not work. Luckily its only about 3500 lbs so with some finesse it will slow down without an issue.

Here is what I have done to try and fix this.

Plug - bent the tabs to make sure I was getting a good connection, used dielectric grease and check with my meter. I have a good connection there. Tried pushing the connector in as far as I could.

Ground - I ran an 8AWG ground from the frame of the receiver to the frame of the trailer. I no not have a grounding problem from the truck to the trailer.

Brakes - I ohmed out the magnets, and checked the shoes. I even went as far as using a separate battery to trigger the wires on the magnet and they stop the wheel just fine.

I'm going to check the ground from the magnet to the frame tomorrow night when I have time to work on it more.

The truck is a 2005 F250 with just under 40,000 miles on it. I would hate to think its wiring in the vehicle. I know if my father-n-law pulls it with a cheapie dumb (not smart like the one in our trucks) brake controller it works fine for him. I guess my issue could be the brake controller but thats an expensive "let see if this works".

I was thinking about adding a basic brake controller to the truck to tow this camper. I have not towed another trailer with brakes with this truck so i don't know how it reacts with other trailers.

[Dave]

Youve got a loose connection in either the truck or trailer

[bulldog55964]

It sounds like a broken wire going to the brakes cause the trailer brake controller doesent trigger off anything other than the trailer brake and ground wire in the plug. Is it just this trailer or always with the truck.You prolly have a broken ground wire on the trailer. The lights have no effect of this cause they can ground through the ball or gooseneck. One way you can check it is to Ohm through Trailer brake and ground on trailer plug. Have some body wiggle wire harness and when it looses connection you found your problem. If all else fails (or harness is not acessable) just run 2 new wires down to the trailer brakes and then you know everything is sound.

[MPTonyT]

OK I figured out what the issue was. After pulling the hubs and soldering all of the wires, I backed my truck up to it and had my wife sit in the vehicle and tell me if/when the error popped up on the dash.

I grabbed a hold of the 7 pin (trailer side) right at the truck connector and gave it a yank up and down and it gave me the error. Instead of trying to chase it down I bought a new 8ft pigtail for the trailer off amazon for 28 bucks.

I rewired it in the junction box and added a slightly better chassis ground to the trailer. I took it for a 30 min pull yesterday and never had the issue pop up and I was able to bring the gain down on the controller as well. I believe it was a poor connection in the harness causing this. We will find out this weekend as I take it on a 4 hour trek to the woods.