Welcome to iRV2. I believe you have found a great site.
I had a previous MH where the cables were all the same and not marked. I purchased some small colored ties and marked all the positive cables with red and the negative with black. That solved any future problems.
To answer your other question, I have found that generally white is ground or negative. Don't assume anything and throughly check it out like HD4Mark has advised.
Don & Bev Morgan Weyauwega WI, 05 Itasca Horizon 40KD, 400 HP Cummins, Adopted by a great couple, Toad 07 Saturn Vue AWD, Air Force One, TST 510 TPMS, Mayor of Weyauwega 2007 - 2013, Waupaca Co Board Supervisor 2010 - 2014