A 12 volt draw on battery from a one wire alternator

You need to learn to troubleshoot this ON THE CAR. Forget what the parts stores say. So let's do this. If you get lost, come back with questions.

1.......I assume you now have the old Mopar system hooked up and the "one wire" add on deal is gone?

2......Go to MyMopar.com if you have not and download a service manual for your car free. Some of them there came from guys here

3......While there, download the aftermarket wiring diagrams. These are sometimes easlier to follow but ARE NOT factory and sometimes leave out details.

4.....Give us some photos of what you now have hooked up in the car

5......If 4 is "yes" let's get to troubleshooting..........

6.....FIRST let's see if voltages are reasonable..........

A.........With key on/ engine stopped, the blue field wire at the alternator should have close to "same as battery." This is with ALL WIRING CONNECTED "normal."

B.........Green field wire should be quite low, 1, 2, 3V. Regulator MUST BE GROUNDED. Remove it, scrape around the bolt holes, and mount tight with star lock washers.

C........With all wiring connected, put one probe on blue wire at alternator field. Stab other probe into top of POSITIVE battery post. You should read VERY LITTLE voltage, and the less the better. More than .3V (3/10 of one volt) means there is a voltage drop problem in the harness/ bulkhead connector/ ammeter/ ignition switch. More on that later

D........Make sure battery is reasonably fully charged, preferably with a regulated charger overnight.

E.......Run engine, warm up, let battery "normalize" and measure battery voltage at fast idle/ simulated low/ medium cruise RPM. Voltage should be 13.8--14.2

IF NOT........

F.......If battery voltage is quite low, 12, 11V, measure voltage "running fast" at alternator stud. If voltage is same low reading as at battery, system is NOT charging.

G.......If system is not charging, remove GREEN field wire at alternator, and ground that now exposed alternator terminal with a alligator clip lead. With key "in run" a spark should be seen. This shows field is drawing current, is good. Run engine RPM up slowly watching ammeter or voltmeter. Voltage should begin to rise. IF NOT check alternator field current. READ THE SERVICE MANUAL it tells how in there. Also, with your alligator clip grounding the field, measure voltage, with "key in run" at the blue field. This voltage should be "same as battery." If this is true, alternator is likely bad.

H..........When you grounded alternator field, and IF alternator now charged, trouble is in field circuit/ VR. Hook back up normal. Remove VR connector. Work it in/ out several times to scrub the connections clean, and visually inspect. Now "rig" a couple of machine screws so you can JUMPER the two VR connections together.
Now remove alternator field BLUE wire and alligator clip that exposed alternator terminal to ground. With key in "run" a spark should be seen. Run engine up slowly in RPM. Battery voltage should climb up. This shows field wiring is OK. If this happens, replace the VR. Again, it MUST be grounded.

You can fix this..........these are easy