This just happened to me two days ago on the freeway. No ignition lights (oil, alt, temp). But the engine would turn over.

It was the ignition switch.

I replaced it and everything is fine.
To access it, remove the steering column cover and you can unplug the switch cable and hot-wire the car very easy-.you need the key in the ignition turned to on to keep the steering wheel unlocked.
This may be the source of your problem.

Robert K
1982 Westfalia