2012 f150 fx4 ecoboost.

Probably somewhere else but rewired my 5x8 utility trailer today plugged in the 4 pin connector and lights come on. However, when I turn left turn signal on, both turn signals on utility trailer blink very dim. When left turn signal left on the left light wires on utility trailer become very hot and the pin connector began to melt for that side.

When I turn signal on the right it works perfectly fine.

I have checked the ground wire and it is solid.

i have checked fuses all seem to be working fine

 

Does any other trailer work on your truck? They do sell a test plug. That said, it sure sounds like a ground problem, I rewired my utility trailer, had to mess with grounds.

 

this is the first trailer I’ve towed with it since owning the truck. My trailer only has one ground wire. When I leave my left turn signal on for a while testing it, the plug for the left turn signal at the 4 pin connector became hot and started to melt the plastic around it. Re did the only ground multiple times and same issue.

 

The vast majority of wiring problems are ground related. Have you done the easy thing and ran a set of jumper cables from the truck frame to the trailer frame? You didn’t say if the trailer was steel or aluminum, but aluminum can be a little tricky to get a good ground. However, With the plug getting hot, I’d say you have a short somewhere, possibly in the molded plug itself, but more likely in the left turn signal housing. You didn’t mention what kind of lights you have, but those old school plastic housing are notorious for problems. One last silly question here, and I say this from personal experience, but, you’re not colorblind are you?

 

never hear of the jumper cable. How do I go about that? Trailer is a 5x8 steel utility trailer. The plug gets hot only on the left turn signal pin and the wire for the left turn signal all the way to the turn signal will get hot. I bought the Hopkins trailer lamp kit from Lowe’s. Am not color blind.

 

Most likely a short in the plastic light housing. Is the wire rubbing or pinched between the housing and the frame? Is there a removable lense on the housing or is it sealed?

 

An easy test to isolate truck vs trailer problem, find a friend, neighbor, trailer somewhere, and plug into truck. Some of the connectors under back end of truck could be a little goofy, maybe unplug each one, evaluate, clean, squirt with a dielectric spray, or wd40, and reassemble.

 

Sounds like you cross wired the right turn signal or double connected something.

Follow the wiring diagram and make sure you have turn signals and brake lights correctly connected.

 

Wiring on trailers seems so hit and miss. I've ripped out four way wiring harnesses and replaced them to get reliable systems.

When stationed overseas you could buy a complete system, pre wired ready to go from plug to lights which you bolted on, wired to the tow vehicle and they always worked. First time every time. Just one plug system, not the 4 way/7way set ups we have here.

 

checked all wires nothing double wired or cross wired