As I also have an over-charging problem (regularly 15-16V, sometimes up to 17V), I ordered one from oldcarpartsnw for less than $30.00 : OEM NOS Chrysler electronic voltage regulator
I will report its performance as soon as I'll get it
you must test the alternator's field current draw.
If it is supposed to be 3 amps, and its drawing 7 amps then its not fair to expect a voltage regulator designed for 3 amps to survive indefinately.
