Trailer Wiring

[mudduck02]

The Driver's side tail light only gives us a solid tail light, no stop/turn signal. First thought was maybe it was the light itself, put a new light assembly on...same problem. The old wiring run in there was old and probably some corrosion. Ran all new wire and new plug...same problem...I am assuming that I have a bad ground some where... I'm running out of ideas...is there a way to test my grounds??

 

[Turx]

Re: Trailer Wiring

I'd say it is either a ground issue or the plug on the vehicle or trailer. Over the years of towing just about every type of trailer I have found it's best to run a continuous ground wire along with the harness on the trailer, other than doing so you rely on the tongue / ball connection in most cases as the ground.

 

[mudduck02]

Re: Trailer Wiring

Thanks Turx! I will try to run a continuous ground and see what happens!!

 

[Silvertip]

Re: Trailer Wiring

Before you knock yourself out running new wires -- determine "why" you need to run a new wire(s). You have not done that. You can run an entire set of wires and still not have it work if the juice is not getting to the trailer via the tow vehicle harness. VERIFY that you have left turn, right turn, tail and ground at the TOW VEHICLE. Then VERIFY that you have all functions at the head end of the trailer harness. A straight pin stuck into a wire serves as a good test point.

 

[mudduck02]

Re: Trailer Wiring

The tow vehicle harness is working properly, have tested that. We ran a brand new wiring harness all the way back to the light.The right side works perfect..the left side I can not get any stop/turn lights. At one point when we'd step on the brake the light would get dimmer....which would have to tell me I have a bad ground somewhere....??

 

[Silvertip]

Re: Trailer Wiring

Did you check the bulb to make sure it is not installed 180 degrees wrong. Yes -- people do get this wrong very often. The sockets and bulbs are keyed but people still tend to force the bulb in wrong which can create the issue you have. If everything else works, you don't have a trailer ground problem but you probably have a lamp ground problem. In other words the the lamp assembly is not being grounded when the attaching bolts are tightened.

 

[jay_merrill]

Re: Trailer Wiring

I agree that you should start at the vehicle, to make sure you are getting correct "signals" from each of the harness contacts. Beyond that, I also agree with the advice in regard to grounds. I have seen all sorts of weird things come up, due to a bad ground. They range from no lights at all, to cross-talk between the turn signals, to tail lights going out completely, when the brake pedal is depressed.

One of the things that I Finally did to get rid of shorts, worn wire insulation, etc., is to completely rewire my trailer and encase all of it inside of split case, plastic conduit. I haven't had a lick of problem with my trailer wiring since.



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