check the Battery box for knife switchs if not there Install 2 one on each set of batterys then You can diss.all of them .I do think the dash 12volt cut off is for emergency use it operates a relay if I remember so some juice will still be used its a pain to check the Batt.water but do it 2 times a year or more if water goes down! I had a little mirror for that job it was still hard to see and refill the damn things but had to getter done lol Lots of work till You get used to the things that have to be done I sure do not miss the M.Home at all lol Bushman
That switch by the shift is to swing Batterys if You need to have more power to start the motor for emergency use only hope You never need it You have a problem if You do called DEAD Batt.....