Congratulations, the results sound about par for the course with these Hitachi's. A lot of the time I get calls from people of what is wrong that causes such and such, and alot of the time it is not as cut and dry as change sensor A, I have a proceedure for trouble shooting that works for me, and I have been successfull with however I can't write it down because it is more of a personality than a proceedure, some people would like you to get in and out in an hour, have an answer and machine fixed for $50, thats just not how it works, sometimes diagnostics is verifying systems are good in order to rule them out, like your wiring being reversed, seems simple to verify wiring, and 9 times out of 10 would be correct, but look you caught the 1 out of 10 that needed it. Sounds like you had the diagnosis part handled, we just provided encouragement!