Alternator and electrical basics with a multimeter

Some simple tests:

I tend to think of these systems as, the output circuit, which comes off the big stud, the big black wire, that is the output, goes through the firewall connector, through the ammeter, branches off to feed power into the car, back out through the firewall connector on big RED, through fuse link,and to battery

Next the field / control circuit. The dark blue "run" wire which feeds ignition system branches off to feed the VR IGN (ignition) terminal, and the VR MUST be grounded. Through the VR, and out on green to the field terminal on the alternator, through the field, which is simply an electromagnet, and to ground through the second brush in the alternator

Possible problems are, a break in the output circuit, preventing alternator output from reaching the battery

Breaks in wiring / terminals

A break in the field wiring, preventing igntiion "run" voltage from reaching the VR, or actually in the green wire, which has happened (guy got the green wire pinched under a rocker cover!!)

Bad VR

Bad alterator

SO.............................Remove the green wire from the alternator field, and rig a jumper wire from the alternator field terminal to the battery. In quiet, subdued lighting, you may hear and or see a very small spark if you connect/ disconnect that wire.

Now start and run the engine, slowly bring up RPM, and see if the ammeter charges. Monitor battery voltage and see if it comes up with a multimeter. Try not to let it go above 16V

If this does not charge, check the output circuit. With the same field jumper in place, transfer your meter to the alternator output stud and run engine again, see if that reading comes up. If not, if it remains below 13V the alternator is not charging. Either repair or replace it.

If the alternator DOES charge with this jumper, not check your VR wiring.

Connect everything up normally again. This time, disconnect the two VR wires and rig a way to jumper between them, AKA connect the blue and green VR wires together. Again, start, run engine, see if it charges. If so, the VR wiring is OK, replace the VR

If you do not have one, run over to MyMopar.com and download a factory service manual, as well as one of the aftermarket wiring diagrams, which are now inexplicably a PITA because they are zipped. Those diagrams are NOT as complete as the factory ones, but can be somewhat easier to follow I use both

Once you run these tests, post back and we will go from there. Once you get it working you MAY NOT be done, as the ammeter circuit may be damage, and also voltage drop in old wiring can cause OVER charging.