Hi folks! Well, dumb is as dumb does with my 2003 Class C Chateau. I crossed the + and - poles on my battery and drove 100 miles. The minimal result was now the interior components (lights, etc.) ...
Check for a couple of large fuses on converter...they are 'reverse polarity' fuses.....blow when battery is connected backwards. Probably 40A...two. Could be on front, side, back on converter