Running lights short truck fuse

[slevar]

Hello
I have a 2016 265RLS, a few months out of warranty.
My issue is with the running lights blowing the fuse in the truck. When the trailer is stationary, lights work fine. However sometime after the trailer is moving they go out.
I’ve hooked up my truck to another trailer and driven around for 15-20 mins, no issues. So I do think it’s the truck. Fuses are spec from ford.
This was actually”repaired” when the trailer was under warranty, however obviously not fully repaired.
I suspect the running light wire has been scraping on metal somewhere in the trailer. I have requested a wiring schematic from Jayco but just wondering if anyone has seen this before and might have a clue to a possible problematic area in the trailer.

[slevar]

OR. Does anyone know where the junction box is that connects the main trailer cable with the individual lights ?

[RogerR]

Somewhere you have an intermittent short. Trace every where you can find and look for potential shorts where it can vibrate or bounce with movement and touch the frame. Could even be in one of the lights.

I would start with the wire comes out of the trailer plug and go from there. You may have to crawl under and look around.

I had to pay a repairman who had a radio device that could detect the spark as the wire shorted out. In my case it was a heavily corroded marker light.

[slevar]

Yes it is a crazy situation. The trailer cable disappears into the overhang for the pin box. I’m thinking there is junction box somewhere for the single brown wire to connect the other 13 lights.
And of course the bottom of the trailer is sealed so I’ll end up taking that off.
I haven’t had all the lights apart yet. But I will do that, it makes sense...

[4U2C]

Any luck? I have a similar issue on a 185BH.

[veafer]

We have a 2018 265rls and had a problem with the outboard lights not working on our 1st trip out. There is a 4x4 electrical box on the frame right behind and below the battery. A ground wire in the box was loose in the wire nut connecting the wires. Used a larger wire nut and taped it up and have had no problem since. I don't know how to attach the link, but it goes into detail on how to trouble shoot the problem. Maybe you can click on my profile and check out my threads?

[4U2C]

Originally Posted by veafer

We have a 2018 265rls and had a problem with the outboard lights not working on our 1st trip out. There is a 4x4 electrical box on the frame right behind and below the battery. A ground wire in the box was loose in the wire nut connecting the wires. Used a larger wire nut and taped it up and have had no problem since. I don't know how to attach the link, but it goes into detail on how to trouble shoot the problem. Maybe you can click on my profile and check out my threads?

Thanks. Will check it out.

[slevar]

I just saw this reply about the ground block by the battery. I’ll have look today. Had many lights apart yesterday, other than a tail light socket and bulb with a lot of rust I saw nothing wrong with any connectors when I pulled them out of the holes. My brother in law, who has an electrical background, tells me that socket and bulb won’t be causing my fuse shorting problem. I’m going to replace them and put dielectric grease on anyway.
Has anyone out there tried to re-run the green wire start to finish? Pin box to tail lights ?

[4U2C]

I forgot to post my solution. I found a loose wire in my 4wire to 7 wire adapter for my trailer that was for the running lights. My friend towed the trailer with a proper 7 wire and didn't have lighting issues. It occurred to me that the only difference between the setups was my adapter.
Hope you found your wiring issue.

[slevar]

Thanks for your update. I just have a straight
7 pin connector. I’ve worked my around most
Of the lights. Nothing seems to be a problem.
Could be internal between the front and the back of the trailer. Also going to double check my truck connector. I’ll keep you posted.

[slevar]

Well I finally found the problem the dealer couldn’t
Took off all my marker lights and looked, at least as far as I could , for damage.
Mounting screw on second last marker light went through a wire causing it to short against the frame. .
I have to say thank you for all the help from the good folks on this site.
So check all your lights!

[4U2C]

Glad you found your issue!