Not good at electrical,need help....128 not charging ..changed volt reg.( corroded inside) I've tracked field wire to new reg ,Tracked batt wire to ign. sol., running reading across batt. 12.27..not running 12.57 across batt. I've jumped from pos on batt to field on gen to polarize...overnight drained batt. no extras,no lights ign off... dash gauge reads backwards like discharging...... input please