electrical glitch in headlight- suggestions?

[gweaver]

The situation:
I've got a euro headlight switch, euro headlight and HID low. I did the mod that modifies the switch so that the middle position is the low beam, and the left position (normally headlight on) can be used to control a set of aux lights. I found the mod here, can't find the thread now.
Anyway...there's something going on somewhere in the wiring- the only way to get the HID bulb to light is to put the high beam on and trigger the 'flash to pass'. Even then, when the trigger is released, HID goes out. I disassembled the high/low switch cluster, sprayed it out with electrical cleaner. Worked last night, when I closed it up- this morning, no joy.
I'm going to pop the headlight out and double-check the wiring and clean out the euro headlight switch, but at this point, I'm at a loss. Everything was working, so I know the original wiring from a year ago was done correctly, but something's obviously changed.
Any suggestions on what else to look for?
Cheers,
Greg