Simple fuse box fix?

If the red at the ignition switch has power you should have headlights, double check?

Also with your light on the ignition red, reach up under and wiggle a few things, the harness, and see if it comes / goes

You can't really test much with the connector apart like that, as that feeds the battery INTO the interior, and then back out through the ammeter circuit to the alternator................That is, leave the connector connected and probe one side of it Also, INSPECT the mating connector at the bulkhead for damage

(Has the wiring been modified?)

At this point I would retest, and see what you "don't have...........that is,.........making CERTAIN the red at the ignition is "hot" see if the ignition switch activates anything at all......

any accessory? wipers/ radio/ heater?
Does it crank?

Does that red go DEAD if you try to activate anything at the key?