92 Civic 4dr LX-stock stick

I turn the key to position one, fine. I turn it to position 2, fine. I turn it to start and the dash lights, radio, clock (everything) shuts down. All electrical accessories are off.
Turn the key back to try again, same thing. Sometimes the electricals don't even come on at all, until something resets itself.
I swapped out the main relay, checked all under hood fuses and connections and checked all dash fuses and wiggle some wires around.
I finally turn the headlight switch on and try it-fires up.

Did it twice today. The second time turning the headlights on didn't work but, I stopped at the parking lights and that worked.

Related somehow or was it just a coincidence that it fired up when I turned on the lights?? I was thinking the ignition switch was shorting out somehow until the light switch worked.

This is my courier work car and it gets twice the mileage that my old BMW gets, so the faster someone can help me, the more cash I save. I will be replacing the headlight switch, just to see.
ANY ideas appreciatted!

 

Wasn't the ignition switch or tumbler, or the light switch , or the dimmer switch, or even the whole fuse box (thinking it was the integrated control unit). It was the friggin positive battery cable. Must be corroded inside.

What a PITA to find, but simple to fix. Of course I had all of the other parts to swap in and try, but I don't have that cable.