I have tried 2 converters to convert my 5 wire isolating harness to 4 wires. Niether or them has worked. I saw a post on this not long ago but cannot find it now. It is a Bushtec V2 hitch and the isolating harness has power and all leads work from the Isolator. It has to be the converter but I have tried 2 seperat models. Any ideas?