It's possible that the converter box on your Curt # C56190 has gone bad, but typically something like this is caused by a short in the system that would need to be fixed to avoid the issue again. From what it sounds like, I believe this can be isolated to the tow vehicle and I recommend that you begin by checking the wiring for any damage that might be visible. I also recommend checking the trailer plugs and cleaning them off so that they're free of dirt, debris and corrosion.
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