OK.
After spending 40 minutes of my precious time
digging around turn signals and checking front light bulbs and sockets, I've discovered that my "winterization guy" left me a present - disconnected front right turn signal!
With that out of the way, my brake light modulator is still NOT functioning. I changed the setup back to stock and brought the modulator home. Does anyone have any idea what could be wrong with it (besides faulty circuitry inside the unit) or why it may have burnt out (IF that's what happened) when I barely rode the bike last season?
Since the stock setup works fine I don't think that there are any grounding problems.