Electrical is gone

You need a wiring diagram. You can find many by searching FABO. Besides just looking at a fuse, it is invaluable to measure the voltage at both sides of the fuse (rel. to a good ground), using a multimeter or even a test light. My father had us suffer for years without AC in FL because the blower's fuse looked good, when it was actually melted at the very end.

In my 65 Dart, the interior lights come off the Instrument Feed line and the blower off the Accessory Feed line. There are individual fuses to each device. Both lines come from terminals on the ignition switch, so that could be the common culprit. However, the switch may not be getting +12 V at its "Batt" terminal. That should be the same as the black wire at your ammeter. Not sure why your running lights work. It looks like the headlight switch has 2 sources: "B1" and "B2". Both come from ammeter blk, one direct and the other via a fuse shared with the stop lights. However, I don't know which one controls which output (many) on the headlight switch. Best guess is that your ignition switch is getting power (since you have running lights) and is thus faulty. A multi-meter would dispel guesses. I got several free from Harbor Freight.