Ditto. Same deal in my 1996 Voyager and I recall in my 2002 T&C. The alternator field is the same "isolated, 2 terminal" design as in 1970-80's Mopars, just a different connector. One terminal gets IGN and the other is shunted to GND to control the field (low-side control). Problem is that Vreg control is integral w/ the PCM. But, as 67Dart273 mentioned, many clever people have figured to just intercept the wires and control w/ an external Vreg (1970's). I wouldn't hack the factory harness, but just unplug it and use a connector from a junkyard vehicle (many there now), wired to a nearby Vreg.
