Alternator Troubles! 1973 Plymouth duster 318

In a nut shell, you appear to have a isolated field alternator.

The voltage regulator regulates the ground side of the field cir.

One of the 2 field wires supplies a constant 12 (nominal) volts.

The other supplies a variable ground.


The fact that you have 0 volts on both wires suggests that the constant feed wire is not supplying the required 12 V

That is where I would start


Now for the required...

Go to mymopar.com and download your cars or the closest to your cars year Factory Service manual.

There are also electrical schematics there as well .


Watch this video.