put, your heads together,i have a 2000 ram van with a 318,my alternator locked up, i replaced it with a new one, it started charging 18 volts, not good!
i have since replaced it with another, and a new pcm, same problem, iv checked all the fuses and wiring and still goes to 18 volts.
i have cut the field wires and added an external voltage regulator, still 18 volts!
mr alternator on u tube says the voltage regulator at 20k ohms should read 1.75
ohms, i cant find one. they all read from 5.75 to 19.24 ohms. any ideas????

 

You lost the ground bond from the engine to the body.

 

actually, i have added a ground from battery to body and regulator and from the regulator to the alternator.
im thinking about adding the pcm into the ground loop, what do you think???

 

Sounds like you've got it covered.