Trailer lights failing every year

jethro · 11-04-2009, 06:15 AM

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.

OU812 · 11-04-2009, 06:33 AM

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.

jethro · 11-05-2009, 11:34 AM

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

Janster · 11-05-2009, 11:39 AM

Quote:

Originally Posted by jethro

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.

Danosabre · 11-05-2009, 11:46 AM

+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

bb609 · 11-05-2009, 08:41 PM

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.

BakoTruck · 11-05-2009, 08:45 PM

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.

11-04-2009, 06:15 AM	#1
jethro Junior Member Name: Geoff Joined: Aug 2009, #21734 Location: Southern NH Gender: Male Posts: 14 '04 2.7l SR5 2004 Xtra Cab Automatic	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.

11-05-2009, 08:45 PM	#7
BakoTruck Damn....not another best oil thread Joined: May 2009, #16674 Location: Bakersfield, CA Age: 23 Gender: Male Posts: 673 05 PreRunner TRD 2005 Access Cab Automatic 4.0L V6 FI DOHC 24V Stock for now, I plan on adding aftermarket wheels and other items in the future.	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. __________________ Approximately 80% of our air pollution stems from hydrocarbons released by vegetation, so let's not go overboard in setting and enforcing tough emission standards from man-made sources. Ronald Reagan

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11-05-2009, 11:34 AM	#3
jethro Junior Member Name: Geoff Joined: Aug 2009, #21734 Location: Southern NH Gender: Male Posts: 14 '04 2.7l SR5 2004 Xtra Cab Automatic	Hmm, well with each harness a new ground is installed. But I gues I should check that out before replacing the damn thing...

11-05-2009, 11:46 AM	#5
Danosabre Member Name: Dan Joined: Oct 2009, #24388 Location: Gardner,Ma Gender: Male Posts: 59 09 TRD Off Road 2009 Access Cab Automatic	+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

11-05-2009, 08:41 PM	#6
bb609 O.F. Joined: Jun 2009, #18509 Location: NH Gender: Male Posts: 356 Tacoma TRD Sport 2009 Access Cab Automatic 4 L Bilstein 5100's all around Air Lift Flowmaster 50 Duals Arctic Bar Leer 550 Bedcover	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.