72 Swinger not charging battery

67Dart273 said
You still have it wrong. First I never said the blue came from the battery. I actually SAID it was switched 12V. I know ALL ABOUT harness drop, and all I can do is go by what you said, which is 8V

THE VR DOES NOT EXCITE THE FIELD. It merely controls the field current from the source, AKA the blue from the switch.

WHAT CAUSES OVER VOLTAGE from the VR circuit is the voltage drop in the blue "run" circuit as seen AT THE VR. That is because the voltage drop makes the VR "think" that voltage is low, so it ramps up field current. This problem is NOT caused by the field circuit. It is caused completely by voltage drop in the ammeter, the bulkhead, and the "ignition run" feed circuit, and culminates AT THE VR ign/ power terminal

One way to address this drop is to cut the blue ign "run" lead coming out of the bulkhead, electrically. Run the bulkhead end to trigger a relay, and connect the engine bay end to the switched contact. Feed the power contact from say, the start relay with no12 and a fuse or breaker.

IGN 1 puts out well below battery voltage which is why all it does for the ignition EFI and fuel is trigger a relay, as you described above.
This was the first thing I did weeks ago as I suspected the voltage from IGN 1 may not run an HEI distributor.
I needed a relay anyway for the EFI and fuel pump.
I looked earlier at what I did when I wired in the relay and realized the 2nd blue wire on the trigger side of the relay IS the VR/alt blue.

I also understand how the VR works. Perhaps excite was the wrong term. The VR controls the strength of the field based on batt V by manipulating the ground on the green wire.

When I just jumped battery + to the blue field wire bat voltage jumped to 13.7V

I'll separate the blues at the firewall, continue to trigger the relay with IGN 1 from the key, and drive the alt/reg blue from the output side of the relay so it's batt V AND switched.

Thanks.

Edit; the harness on this beast is even worse than I thought. I can't find where the blue to the alt is connected to IGN 1. The VR blue was the other wire I HOPED was connected to the alt blue. Peeled off layers of electrical tape and found splices all over the place, splices to different colred wires that go God knows where... Maybe I will spring for one of those HUGE color laminated wiring diagrams.

Also something I forgot to mention is the ammeter in the dash indicates the battery is charging. I don't know how that could be because I tested the V out of the battery terminal on the alt and it shows the same as battery V. Doesn't the alt batt terminal go through the ammeter?