Polarity is not the issue, the problem is if I use a commercial reducer to drop it to 6 volt the engines do not work, none of them. They are all 6 volt motors from before I upgraded the system.

So has anyone done a switch to 12v from 6, and did you drop the volts for the fans, and wiper? If so what did you use?

Right now I think I will probably just run em till they die on 12v. Which may never happen, as they really do not seem to be over powered, the engines are not getting hot, the switches for the fans have ceramic covered resistors in them and they get hot, but I think they do regardless of 6v or 12v.