Both sides at once, or just one side?

I have a very similar problem.  On my 2003 325i, my driver-side xenon
light flickers on occasion.  Worse, the light actually will go out
completely for an extended period of time (it'll sometimes be out until
the next time I start the car...sometimes for a few days).  I've
noticed the following:
Light has gone out in any of these situations:
1) Idling
2) Moving
3) Upon starting the car

Light comes back on only:
1) Upon starting the car

I've taken it the the service center many times, and each time they try
replacing one thing or another, but it never fixes the problem.  (I'm
currently researching NC lemon laws)

TMann