Dash headlight switch problem? Ground? (Which ones?!)

Cunegonde has had an intermittent passenger lowbeam headlight outage. Highbeam worked on both sides. All marker lights, turnsignals and 4-way emergency flashers worked fine.

Now only the marker lights work.

Now she has NO headlights - low or highbeam - and NO turnsignals or emergency flashers. I can hear the flasher relay clicking and tested it with a new one. No difference. The emergency 4-way flasher switch used to light up. Now it doesn't.

Earlier, I had suspected the passenger headlight ground wire was faulty and traced it back to the fuse area ground star. Cleaned it up, checked for voltage, nope. Cleaned all visible connectors. No change. 

Suggestions of likely culprits?