I have a 4x8 Utility trailer. When I went to hook it to the truck the 4pin plug wont fit. The one on the truck has a weather proof shroud that is the same size as the shroud on the trailer. I trimmed the shroud on the trailer and it fit. I had parking lights but when one tursignal went on the both flashed and when you hit the brakes all the lights went out. I bought and installed all new lights and wiring. Others were corroded. But, it still doing the same thing. I then put the towing relay in, still the same thing. It is all wired correctly because it worked on the chevy I traded in. I havn't checked the plug on the truck with a volt meter yet it has been raining all day. Any ideas?????

 

I'll ask this question and don't mean to insult your intellect but is the wiring harness on the trailer grounded? I had this problem on another ford, grounded the white wire and worked fine.

 

can u make that all happen with the 4 pin plug ?
i use the 7 pin with my trailer brakes all is good here

one for ground
one for left signal
one for right signal
one for brake lights
no night time lights
no fourway flasher

 

Tried grounded it in mutiple places, still no luck, when the weather gets better I am going to check the ground with a meter. But it is the same ground point I used when it was hooked to my chevy.

 

I havn't tried the seven pin, I need the adapter.

 

Yea, I had to trim my plug a little because of that weather shrowd. The lights work fine though other than that...

 

Use a test light on the truck