My dad needs retire this truck, but he won't, so I am stuck fixing it... Here is what is going on...

The alternator is over-charging... I have changed the alternator, voltage regulator, the plug on the voltage regulator, and put a new battery in it...

I have done some voltage checking, and there is 12 volts on the field wire, with the truck off. I checked my bronco, and I don't have any voltage...

what could cause this?

 

unplug the regulator and see if you've still got 12v at the field wire. if you don't the reg is prolly the problem. if you do, then you have to find where the field wire is shorted to positive- probably in the harness between the reg and the alt.