Trailer lights failing every year

Ok, so I have had my '04 Tacoma since November of 2003. I tow a snowmobile trailer all winter long, and it seems every year I am replacing my trailer light harness. Is there a company that makes a better harness? I was having a garage install one every year, but then realized it was the same thing I could buy for $38 at Advanced Auto Parts. It takes about 20 minutes to install, so i do it myself now.

But without fail, and usually not much more than a year after I install it, all my lights fail. The only fix seems to be taking the harness with the little converter box out of the system. It usually happens when I am a couple hundred miles from home.

So does anyone know what is failing? Is it the little converter box? Is there a company that makes a bombproof harness? I don't mind spending more money if the harness lasts longer. Nothing sucks more than having all the lights fail on a snowy mountain road hauling a loaded trailer. Should I try and waterproof the converter box better? I was thinking of mounting a little dry box and putting the box inside that.

Any suggestions are welcome. Maybe I just need to carry a spare harness with me and the tools to install it on the side of the road. What a PITA.

 

There must be a common denominator in this case. Once a year they all fail? Trailers are notorious for poor grounds. You replace the harness, it works for awhile, then out again. But by replacing the harness you have disturbed the grounds. Check the grounds, clean em. There are products out there to insulate grounds like Zep contact cleaner and sealer for use on battery posts.

 

Hmm, well with each harness a new ground is installed. But I gues I should check that out before replacing the damn thing...

 

I'm just guessing here...so take this for what its worth...(a grain of salt)

When you replace it....do you inspect the old harnass? Do you see any obvious problems? Are there areas that are wearing through the insulation of the wiring? Are there any burnt spots/bare spots, kinked spots, etc.

Is the wiring harnass a plug & play? Does it involve you to solder anything? What are you plugging into/soldering into? etc etc etc.

 

+1 For the ground. I had a problem with my ground wires, had to take em all down to bare metal then covered em with dilectric (sp?) grease

 

Road salt in NH eats them pretty quick. Do you hose/wash it down with fresh water at all? A dab of white lithium grease in each of the sockets and connections helps too.

 

I would agree with what everyone is saying above, but I also have another suggestion. Are you using a brighter bulb or light? A brighter bulb that is not rated for that harness could maybe cause it to go out faster?
I'm not sure just something I would throw out there.