Trailer wires melting.

**REAKtion4** · Oct-01-2010, 01:56 PM

I have a 4 pin trailer light system with submersible LED trailer lights. I have not had any problem until now. I noticed the last time I unhooked the trailer the smell of burning rubber. When I looked at the adapter that connects the trailer 4 pin to the 5 round car connection one point was melted and burnt. I looked at the trailer wires and the brown wires that is paired with the yellow wire has the insulation melting off roughly until about half way down the trailer. I have a 2004 Toyota 4Runner that it is plugged into. Is it a short in the trailer? Vehicle? or something else. Any advice would be greatly appreciated. I bought a new set of wires. Before I install them I would like to find the problem out first. Thanks in advance.

**Fishbones** · Oct-01-2010, 04:42 PM

Short in the trailer, what size fuse do you have in your truck? It should have blown.

**cj5orion** · Oct-01-2010, 04:49 PM

definitely a short.
probably jus the ground wire ? thats first !
brown n yellow....if I remember correctly ?
brakes n turn signal ?
simple idiot light with the help of a bud (or a mirror),couple minutes in the driveway,
maybe a splice?,check the fuse,drinkin a beer,problem solved

**fishstomp** · Oct-01-2010, 05:10 PM

The ground wire is supposed to be "shorted". It is attached to the frame of your trailer. Hook one lead of your ohm meter to the trailer frame and then put the other lead to each male pin of the trailer plug one at a time. The one that has no or low resistance (low number on the display) is shorted. The yellow is your left turn/brake, the green is your right turn/brake, the brown is your running lights. The white wire is ground and will have no resistance. If the white (female pin) has high resistance your ground lead is bad.
Trailer Wiring Diagrams | etrailer.com

**fishstomp** · Oct-01-2010, 05:43 PM

When you cut the old harness at the LED lights, put your ohm meter from the frame to the yellow, then the green, then the brown wire. If you read anything you had a short to the frame. Then check the white wire in the old harness to the frame. You should get a very low reading. If not the ground was open. If this checks okay, check from the frame to the yellow then the green lead going to your lights. They should read about the same. If one reads much lower, the light has a short. Then check from the frame to the brown wires at the lights. They should read about the same. If one is lower, that light is bad.