Would Performing a Battery Test Fry a Trailer Wiring Harness on a 2012 Ford Focus

Question:

I recently had my 2012 Focus Titanium Hatchback serviced while a recall was being performed at a local Ford Dealer. One part of the service is a battery test, I noticed a few days later that the yellow fuse holder wire had been ripped out of the ring terminal that was left attached to the positive terminal. I also noticed that there was a smell of something burning for a few days after that while driving the car. I suspect that the wire being removed from the ring terminal somehow caused the black Convertor Box to fry. Is that possible? Ive checked all the connections, the fuse, followed the wire under the car to insure it had not been pinched or cut, etc. and the trailer lights which work using my other vehicle still will not work, they receive no power at all.

asked by: Dave

Expert Reply:

If the yellow fuse holder wire from wiring harness # 118549 was pulled out at the battery then it would not have done anything to the converter box. What might have happened is some part of the system when attached to the battery touched something else and melted or burned something but that is speculation.

The trailer lights get the power from that connection to the battery so if it is not connected or the fuse is blown then it will not work. If it is all connected and the lights are not working still then it probably was a short to the converter. Whether or not it was caused by the Ford dealer I can't say but if it was working before they fiddled with it and now it isn't then its possible the battery tester machine fried it and in a panic they yanked the cable out.

expert reply by: Michael H