Troubleshooting Trailer Wiring that has Blown Up Two Tail Light Converters

Question:

I have a 2005 Dodge Magnum R/T with load leveling and tow prep, but it did not come with a factory hitch or converter. The original converter installed failed after a few years. It swelled up and was obviously melted inside. The replacement converter just burned up yesterday with awful smoke - the unit is literally charred. It had block its 10A fuse a week earlier, but the unit was visually fine at the time of replacement. The trailer is a single axel with four running lights and two tails. The tails are sealed LED units and the running lights are amber small bulb incandescent. I dont think Im exceeding the capacity of the converter. The converter is well grounded and gets power from the battery. Any idea why Ive burned up two converters?

asked by: Jim B

Expert Reply:

Although taillight converters, just like any other electronic device have a set lifespan, losing two of them in rapid succession tells us that something is going on.

The two most likely causes are a short circuit in the trailer wiring and overloading the converter.

First, check the wiring on your trailer. Beginning at the trailer connector and working your way back to each lamp, closely examine the wiring. Wire insulation can become brittle over time, look for any cracked or worn wire insulation that is allowing the copper conductor to contact the trailer frame. Likely spots to check are places where the wire is in direct contact with the trailer frame such as points where the wire is clipped to the frame or where wires pass through holes in the frame members. Also make sure that the bulb sockets in the running lights are not corroded. Immersing the trailer connector can also cause a short circuit. If you tow a boat, make sure to unplug the trailer connector before backing into the water.

The extra running lights you have might be exceeding the 9.8 amp capacity of the converter. If the trailer wiring checks out fine, using an Taillight Converter like part # 119250KIT would have enough capacity to handle your trailer lighting. The #119250KIT would hardwire into your tail light circuits, rather than plugging inline like the previous harnesses you have used. If you have already replaced the converter, replacing the incandescent lamps with the equivalent LED units would reduce the amperage draw and likely solve your problem.

I have linked you to our trailer wiring FAQ as well as a link to a trailer wire troubleshooting video.

expert reply by: Mike L