Battery Not Charging

Don't overthink. I'm trying to cover "possibilities." I tend to divide things into sections in no particular order

1...Parts bad IE the alternator and regulator While it's difficult to test the regulator, you can test the alternator on the car, and eliminate or confirm

2....The output wiring, that is the black output wire, goes through the bulkhead, through the ammeter, back out the bulkhead, to the battery. You need to confirm that is OK, part of which is done above

3....The field wireing, the blue, green going from the ignition switch and from the VR

Basically you are feeding full 12V through the field (the two small connectors) in these tests. This SHOULD cause the alternator to go "full output" depending on RPM, and "if it works."

One last thing I forgot........make sure the belt is tight!!!