Alternator Not Charging

I wish you would have come back before "throwing money" at the problem These are fairly easy to troubleshoot I divide the problem into areas

1...The charge output wiring, that is, the circuit path from the alternator, through the firewall connector, the ammeter, back out, and to the battery. There can be a bad connection in that path

2....The field wireing, same deal. We recently had a guy with a broken/ pinched green field wire, which only has a simple job---from the VR to the alternator field terminal

3...The alternator

4...The regulator

SO WHAT DO I DO?

Put a voltmeter on the alternator output stud and ground. You should read "same as battery." "Rig" a jumper/ alligator clip wire from the alternator field terminal to the battery. In subdued lighting, you should see a small spark as you connect/ disconnect. Start the engine and slowly bring up RPM, while watching the voltmeter and ammeter. The voltmeter should rise above 12.whatever, and the ammeter should move to the right. Do not rev up the engine and allow the voltage much past 16V

If the alternator stud voltage does NOT rise, the alternator is bad. If the alternator stud voltage rises, but the battery voltage does not, you have a bad connection in the charge line

If it DOES charge, you are down to field wiring/ regulator

If it does charge..............

Disconnect the two wires at the voltage regulator, green and blue, and jumper them together. Again run the test. If it charges, replace the alternator. If it does not charge you have a wiring problem in the field circuit

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IF you "fix" it and it charges YOU ARE NOT DONE YET. This is because most of these old girls have voltage drop problems which cause OVER charging. To check this..........

Turn the key to "run" with engine stopped. Stab one probe into the top of the battery POS post, and connect the other to the blue VR wire. Leave everything connected "normal." You should read a VERY small voltage the smaller the better. Anything over about .3V (3/10 of one volt) you need to find out why

That circuit path is battery--- starter relay "big stud"---fuse link---through the bulkhead connector---tthrough the ammeter---through the welded splice---to the ignition switch connector---through the switch--back out the switch connector on the dark blue "ignition run" wire---back out the bulkhead connector---and branch off in the engine bay to the ignition and VR. All of the points mentioned above are suspect bad connections

GROUND: A poor ground can cause overcharge. With the engine running fast idle to simulate low to medium cruise, make this test with all loads turned off and again with lights, heater, etc powered on. Stab one meter probe into the top of the battery NEG post. Stab the other into the VR mounting flange. Again, you want the "less the better", zero is perfect