No Headlight - need advice

I returned from a ride yesterday to discover I had no headlight on my 200 Standard, neither the low or high beam. I've checked the bulb and it powered up for both low and high beam so it is good. I checked the fuse visually and with an OHM meter and it is good.

I've made two modifications from stock to be aware of.
1. I added driving lights through a relay and checked all those connections and they are sound. It all worked for the month of so I've had the driving lights wired up. The driving lights are wired to operate through a three-way switch to be on with the key (both low or high beam), on with "high beam only" or "off". They still work on the "key only" position. The "high beam only" position does not work as the relay trip source is an intercept from the high beam light wire within the headlight assembly. Which is consistent with no power to the headlight.
2. I upgraded the headlight bulb to a 100/80 bulb, following the advice at Chet's Walter's Valkyrie page where he said "The stock Standard wiring will support (for "off road use only" of course) an H4 with the wattage of 100/90 without the need for any wiring overhaul so it's just a matter of replacing the bulb."

I'm at a loss to know what to check next or how to find the problem, anyone have any ideas or advice? Could my switch have gone bad somehow? Not sure what to do next. I'm not a electrical wiring wizard. TIA