Trailer Lights on When 2003 Ford Windstar Lights are Off

Question:

I have a 2003 Ford Windstar with a power converter. Power is coming into converter from battery, but coming out both sides of converter trailer side and vehicle side of converter. When trailer is plugged into vehicle connector, trailer tail lights are always on, even when vehicle lights are off. No brake lights or turn signals work on trailer, but they work properly on vehicle. Has the converter malfunctioned or is this a grounding problem? Is it common for tail lights to always be on with a converter since its wired directly to battery?

asked by: Mark

Expert Reply:

I have a simple solution to a complicated problem. You are using the wrong converter. Your Windstar uses what is called a low-side wiring system. This means that neutral side of the lighting circuit is turned on and off, instead of the positive or hot side. We do offer the correct wiring harness, part # HM40615.

expert reply by: Mike L