Some simple tests you can do. I try to "group" a possible charging problem into the alternator, the regulator, the field side wiring, and the output wiring or "charging wire"
Many guys jump in and jumper the field to bypass the regulator and field wiring. But you have to be CAREFUL with this because a (prevalant and common) problem in the bulkhead connector wiring can mean that the output path to the battery is broken.
1..So if the thing is not charging adequately, judging by the battery voltage, first move the meter from battery to alternator output stud and see how that compares, with engine running to simulate "low to medium cruise." If the alternator output is about the same, likely the charge path is OK. If that stud is sky high, then you have a broken circuit path there
2...If the first check is OK, now full field the alternator. There is a couple of ways to do this, and depending if you have a problem in the field wiring, this could lead you astray. So disconnect the green alternator field wire (comes from regulator) and connect a "clip" lead to ground. You should be able to see a small spark in subdued light. With that wire connected, and key in "run", check the BLUE alternator field to be certain you have "close to same as" battery voltage. So now the blue is OK, the field is drawing current.
Start the car, monitor battery voltage, and see if battery voltage comes up. Don't let it get above 16V. If that happens, turn on all accessories, lights, heater, etc, and see if you can maintain 15V at least. If so, the blue field wiring, the alternator, and the charge path are all OK
3....VR and field wiring. You have already checked the blue. We had someone on here had a green field wire shorted to ground. This can happen, the harness abraids, melts to the intake/ engine, etc
So reconnect the green field wire, disconnect the VR connector. Work it in/ out several times to "scrub" the terminals, and to "feel" for tightness, and inspect for corrosion "Rig" something like machine screws into the connector, and jumper across the two with a clip lead. This will put 12V on the green wire. NOW go back to the alternator and this time disconnect and ground the field where the BLUE was connected. This now, will again full field the alternator, but will be using the green wire and the VR IGN terminal for a source.
Check AGAIN that the thing will charge.
VR: Unfortunately Mopar used both the ignition box and the VR case AS PART OF the circuit. BOTH these boxes must be grounded to operate. Unbolt them, scrape around the bolt holes on the firewall and boxes, and remount with star lock washers.
VOLTAGE DROP: COMMON over-charge problems are due to voltage drop in the ignition harness. To check for this, access the ballast resistor "key" terminal and run your meter from there to battery POS. Turn the key to run............you are hoping for a very low reading, the lower the better. ANY drop over about .3V you need to look into. Bulkhead connector, ignition switch, connectors and wiring in that path. Any drop there is ADDED to the nominal 14V the regulator charges. So if you have 1.5V drop, the battery will "see" 15.5V
Check the GROUND path for drop. To do that run the engine, run this check first with all accessories off, and again, with heater, lights, etc powered. Run engine at "low to medium cruise." Stab one probe into the metal mount of the VR. Stab the other into the battery NEG post. Again, you want the lower the better, zero is perfect
