It's definitely the spike off the solenoid that's screwing with me. I ordered some more "lights" off the Ding How Purveyor, and they're freaking LEDs. Dammit! I did what I was trying to avoid, and put a relay in. The LED indicator works now, but the turn/high beam indicators still flicker when the solenoid disengages. Ima try moving the solenoid ground away, and see what that does. Hindsight being 20/20, I should have grounded the b*tch to the frame.
What really ticks me off is that, of all the doggone, complicated wiring I've done in 30 years, a simple switch, solenoid, and indicator are giving me a straight up fit! GRRRRRR!