Strange things at startup when headlights converted to HID

[jakeru]

I also have the problem of dash lights (I believe alternator, and low oil pressure warning light) coming on sometimes when I turn on my headlights (which have aftermarket HIDs/ballasts). If I have my stereo on, it usually also turns off the stereo (it might automatically turn back on also, but I can't remember.). It only happens sometimes, and the headlights do turn on reliably. But this behavior makes me favor just running the fog lights sometimes.

Turning they key off, and then back on does always temporarily solve the problem, but this can be a big hassle (and potentially unsafe) if you're already driving the car.

I have the aerokit with the fixed rear wing that replaces the powered rear spoiler, so I have no problems (obviously) with a nonexistent powered rear spoiler.

I wonder if adding a ferrite ring in the HID wiring somewhere (perhaps between ballast and lamp) would solve the problem.