Vanaman

Replaced the house batteries, one cable left over that I am not sure what it goes to. It seems to run to the opposite side of the coach into the compartment with the inverter. It looks like a phone line, would with go to the Positive or Negative terminal?

I replaced the 6 volt batters, some how managed to reverse polarity. Got that problem solved and every thing works except the three living room and dining room lights. These are the 12 volt fluorescent lights. I took one down but it didn't seem to have any kind of ballast. I have also checked all fuses and seem to find my self in need of some help/advice. Thank you.