The solid state turn signal switch will work fine on 12 volts...the earlier Distribution box setup wont unless you convert it internally per Amphi's procedure, documented in the Online Maintenance Manuals page OR convert to solid state signals per my conversion page in the Online Maintenance Manuals.
The 3 lever switch doesnt care...it will work on 12 volts fine.
Lord send your Holy Ghost into our hearts and make the desire of our hearts Your Will.
Pro-choice, that's a LIE, babies don't choose to die!!