View Full Version : Calling all wiring experts

03-06-2010, 10:18 PM
I keep blowing the trailer tow fuse in mt 2009 dodge pickup. Its very frustrating. The trailer is about a year old. I change the fuse...and plug light in and they work fine in the gargage. Then on the road the fuse blows and sometimes the back left trailer light blows out so bad the bulb explodes when I check the damage. I can let it run standing still in the garage and everything is fine...but on the road she blows out. I always unplug before i back into water too. What the heck is going on???

03-06-2010, 10:22 PM
if it was me id trace down the wires and see if you can find the prob....i had the same problem...i said heck with it and rewired mine. and put the submercible light in mine...

03-06-2010, 10:37 PM
Sounds to me like there is a wire that has rubbed the insulation off somewhere from front to back. Check them real good for any bare wire.

03-06-2010, 10:45 PM
Do your lights have the sealed housings? Is the failure happening after the trailer has been in the water?

Jig Man
03-06-2010, 11:24 PM
Had a problem similar to this one a few years back. I wound up finding a wire with the insulation rubbed through (between the spare tire and the frame).
Everything would be fine until I hit a bump and the spare tire would short the wire against the frame.
I have never seen a shorted wire pop a bulb though. Sounds like water may be getting to the bulb when it is hot.

03-06-2010, 11:43 PM
You need submersibles anyway, but the problem is probably a bad spot of insulation. The little spring clips that come with the kits were my problem when I had issues. Salt water didn't help either.

03-06-2010, 11:48 PM
look where your harness goes into the frame on the hitch, good place to start.

03-07-2010, 01:37 AM
I had a similar problem with a brand new boat/trailer last year. After many long nights trying to fix the problem, I finally put sealed LED lights on the trailer and ran a ground wire to each light on the trailer instead of using the trailer as ground. I've had no problems since. I still don't know if it was the lights or the ground, but doing both is your best bet.
Hope this helps.

03-07-2010, 11:14 AM
Exploding bulb makes me think that the hot bulb is coming in contact with water and breaking.

I think its time to rewire. The time you spend chasing this problem can easily equal the time it takes to put new wires and taillight set on the trailer.

How many wires do you have in the harness on the trailer? Four, five, more? What colors are they? This will help us find you a wiring diagram to follow.

Cane Pole
03-07-2010, 11:59 AM
I hate trailer wiring. 30 minute jobs easily turns into all day.:mad:

03-07-2010, 12:22 PM
I hate trailer wiring. 30 minute jobs easily turns into all day.:mad:

They will if you try to put a trolling motor or a depth finder on your trailer, LOL. Sorry Cane... had to...

How's the new Johnson running? Find ya any 4 wire barbed-wire fences to test it out on yet?

03-08-2010, 07:21 AM
Exploding bulb makes me think that the hot bulb is coming in contact with water and breaking.

I agree. Wiring wouldn't explain an exploding bulb.

03-08-2010, 07:41 AM
A short to ground is what blows fuses. Does it blow going to the water or coming home. If the bulb blows sometimes the filiament will short out and blow the fuse. But water hiting the bulb while it is hot will make it explode.
Restring the wire, you can buy trailer wiring at autoparts stores all 4 wires are molded together. Most wire yellow left turn-stop, dark green right turn-stop, brown running lights, White ground, Add tape at contact points that hold the wire. There is also tubing that is split you can put over the wiring to help keep it from rubbing through. It is not too expensive. As for the light if you don't want to buy a new one take the lens off and seal it with silcone or a new seal. The silcone makes it hard to change the bulb but if it don't leak the bulb will last a long time. The butt connectors with heat srink works great to splice the wires or solder and tape none of this just twist and tape.Great fishing Cub48