Trailer Lights

[SuddenlySummer]

Thought I'd put new lights on my trailer. I'm ready to pull out my hair. I followed the diagram and they still work wrong. This is what my lights are doing. When I turn on my headlights, the trailer lights light up brightly. When I hit the brake, the trailer lights go out.

When I use the turn signals, both lights flash dimly.

All of my grounds are clean. When you install each light assembly, there are three wires about three inches long coming from each assembly. The driver side light has a yellow,brown and white wire. the passenger side has a green, brown and white wire.

I know that the white wires coming from the assembly are the ground. Each one is connected to the frame. (I even cleaned the frame with a grinder to get a good connection)

On the driver side I have yellow to yellow and brown to brown. On the other side I have green to green and brown to brown.

Help.

[SuddenlySummer]

At the hitch, the white ground going to the lights is also a clean connection to the frame.

[Dave]

Unmount the lights, let them hang and try it. Maybe you pinched a wire when you bolted them in. Did you replace the wiring plug also?

[SuddenlySummer]

The wiring plug is a 2001 Dodge Ram. Factory mounted hitch and harness. That was my focus for tomorrow.I

[Hubcat]

Sounds familar

Sounds to me that you may have a short or a bad plug.
Because you are getting lights your ground seems to be ok.
Check to make sure that you have no bare wires touching each other or ground.
I had a simular problem where the wire went into the trailer before it ran back to the lights got striped from rubbing on the trailer and cause a short.
Another helpful tool is a wire prob, you can use this to isolate the problem and they don't cost much.

Bob

[musky hunter]

I am assuming that the previous light worked correctly. This would eliminate truck wiring as a cause, and you probably eliminated grounding as the cause. I think it's a crossed wire problem in the trailer. To find the cause, you are going to have to trace out what function each pin on the plug from the truck is serving. This requires some sort of an indicator, could be a volt meter or even two wires and a 12 volt light bulb, and an assistant because you can't do it alone. Do this with the trailer lights disconnected, and test and label each pin for brake, right blinker, tail, etc. Then match it up to the pins on the trailer connection and trace out which trailer wires each pin goes to. The trailer wiring has a color code that came with the wiring kit. If it's an older trialer, there could have been several different repairs to the wiring, splices, etc. so assume nothing. Then, see that the correct wires by color code go to the right light bulb element on you're trailer. You're trailer lights are probably the dual function ones,(they have more than one element and the base has two little bumps that the corrent goes to) and in might be possible to have you're trailer light bulbs in "backwards" in the socket. This should help isolate the problem. Good luck.

[hydro]

I hate to sound redundant, but your problem is the ground circuit.

I've chased those symptoms many times on older trailers and it is always caused by rust in the trailer frame preventing a ground connection to the tail lights. One way around it is to run the white wire all the way back to the tail light assemblies and terminate it where they ground. You can also try to clean and correct the frame ground problems but they will just come back.

While there isn't an easy fix, the problem is easy to diagnose by your description of the lights.

[SuddenlySummer]

Hydro,

You hit the nail on the head. So simple! I thought that it was a ground issue. I was grinding down the frame to get a good contact and all I had to do was run the ground wire from the connection back to the lights.

Sometimes you just have to K.I.S.S. it once in awhile!

Thanks.

[huskminn]

I had the identical problem and eventually ended up with the identical solution.....eventually being the operative word there.