Trailer Lights Not Working

[Dubz]

I can't seem to find out why my tailer lights have stopped working. I tow a jet ski trailer which one of the led trailer lights got a little water inside of it which may have cause the initial problem. Now I can't get the lights to work again, I have checked the fuse in the back compartment #78, which is still good and I have check the connections at the light module and connections for the trailer light socket with no luck. I think the problem may be the light module, but the only way to get a light module is by purchasing a complete trailer hitch set. My question would be has anyone else had a problem similar to mine and if so how did they repair there problem or if anyone has any recommendations on what I can do to repair my problem help would be greatly appreciated.

[Dubz]

Bump

[JCL]

Assume you have traced back along the wiring from the trailer lights, to the hitch connector socket, to the BMW wiring harness, and then back to the lighting module, with a test light?

Haven't heard of anyone needing a new lighting module, but I recall that BMW sold it separately to the hitch kit back when I bought mine. I checked, because it was cheaper to buy them as a package than get them separately, so I know they did have a listing for it.

[Dubz]

Yes I have tested it back through the harness and have no power and I've tested the fuses and they are good.

[statdoc]

Something like this is very helpful to evaluate this. This tester will let you know if everything is right down to the trailer connection. If it is, your problem is somewhere in the trailer, not the car.
Circuit Tester

[Dubz]

i do have one of those tester but it doesn't do me any good because I have no power going to the trailer light socket.

[statdoc]

Originally Posted by Dubz

i do have one of those tester but it doesn't do me any good because I have no power going to the trailer light socket.

Well, actually it did you a lot of good. You now know your problem is in the car, rather than the trailer. I had a problem with my own watercraft trailer last week, and when I tested, I found I had no problem with the car. It let me know I had problems with the trailer instead. I didn't have to waste time working on non-existant problems in the car.

[markesq]

I am having a light problem also. The volt meter show current coming out of the plug, but when I connect the trailer no lights. Used a different truck and the trailer lights work fine. I am stumped.

[tomgtv]

I was too cheap to buy the BMW trailer circuit card for $200 bucks and
just had the trailer hitch shop splice the trailer lights in. No problem
with single Jetski trailer.
When I got a new double ski trailer it has a lot more lights due to regulations.
I then got erratic performance. Sometime on, sometimes off. Plus I'd get
that burned out light bulb indicator on dash.

From what I've heard if you splice it in the signal voltage from car is not that strong, it is just what it is, signal voltage. They wire the lights some way
to main electrical to get power to drive lights. I think you're supposed to
get some majical module ( I think they actually put that in my system) to draw
current from battery with cable.

In the end I just bought a brand new set of trailer LED lights that have virtually no current draw versus std incandescent. Wa La..........no more problems. They work great.

[markesq]

Figured it out. The ground wire on the trailer broke off.