Trailer Hitch Problem

[jaco]

I have a problem with the converter box installed on my truck. It converts 3 wire system used in cars to a 2 wire system used in boat trailers. I had it replaced three times since October 2005. According to U-Haul, they installed my hitch, the problem might be caused by me launching and retrieving the boat with the trailer plugged in. They suggested I unplug the trailer every time it goes in the water. I have never seen anybody doing that at boat launch. Has anybody experienced this problem?

[Low_Budget_Hooker]

never.

sounds like an isolated ground loop.

Do the lights blow out?  If so, any pattern?  (just directionals blow, just the directional that is being used, just brake bulb blows,etc?)

[jaco]

The lights don't blow out. The converter does, resulting in random malfunctions of the lights (say left blinker doesn't work, but the rest is fine, next day brake lights stay on all the time, rest works fine etc.) Only trailer is affected, the truck lights work fine. Replacing the converter fixes the problem.

[Team_Dougherty]

I always unplug my trailer lights before backing into the water. It saves on bulbs. As far as your problem goes I would think a short somewhere on the trailer would cause that converter to blow. You should start looking for one.  I have not had a vehicle that needed on of those in a while. But I know when they go bad they do crazy things.  

Paul

[Low_Budget_Hooker]

Check the ground on the trailer for corrosion where they bolt it to the trailer.

[Ben]

I would go with LBH, make sure you have a good clean ground connection where the ground wire connects to the trailer frame.  Also, check and see if they have the ground side of the vehicle connector connected.   Check with an ohm meter, should read less than 1 ohm resistance.

The vehicle adapter use diodes to make it so seperate turn and brake lights can adapted into a single turn/brake system used on the trailer, a bad ground will cause higher inverse peak voltages  than the diodes are rated for, blowing the diode.  

If you continue having the problem, take one of the old adapters, get you four, 5 amp 400 PIV diodes and make you one that won't blow.  It's very simple to make.  The diodes will have a silver band around one end, solder the silver band end of two diodes to the single wire end that goes to the trailer, on the vehicle end, connect the turn wire to one diode and the brake wire to the other, do this for both sides and your ready to go.

[mattfish]

I always unplug the lights even water proof systems can fail.

[Ben]

Actually, unplugging and plugging them may be when he's blowing the adapter.  If this is done when any of the lights are on, the voltage spike created during the connect/disconnect can be great enough to blow the diodes in those store bought harnesses.  Some of those things only run 50 PIV diodes and the spike can be a couple of times that if there's a bad ground.