Charging System Troubleshooting--Blown Ignition Light Fuse?

[ACHiPo]

Well something kinda worked!

I removed the "I" wire from the VR connector, jumpered the R/Y and W/B lugs and reconnected it to the VR. I replaced fuse 3, reconnected the ignition lamp, and removed the fused jumper from the ignition switch.

I started the car, the ammeter rose to 15A, and rose and fell as I feathered the throttle. I turned on the headlights and the ammeter dropped to 5A. Turned off the lights and the ammeter rose back to 15, then the engine died. This whole process lasted a little over a minute, but the charging system seemed to work the entire time.

I restarted the engine, but the ammeter didn't move. I turned on the lights, and the ammeter dropped to -10A, and back to 0 when I turned them off. I shut off the engine and checked fuse 3--it was blown again. Guessing it blew when the engine died or when I restarted it.

I don't understand why the fuse would blow since the "I" was disconnected, basically taking the ignition light out of the circuit?

I ran Patrick's test (I think?), removing the jumper between A and S on the VR connector and grounding the A (Y/R) wire to the block. I removed the fuse (even though it was blown), pulled off the double wire, and reconnected the fused jumper to the ACC terminal of the ignition switch. Turned the key to "ON". Nada. Started the engine. Nada.