Sorry if this is a repost... My 03 TL driver side head lamp will occasionally flicker and then go out completely. Sometimes it happens after 15-20 minutes, sometimes an hour, sometimes not at all. I have noticed when it does do it if im looking at it through a reflective surface (store front, car in front of me, etc), when the light is flickering trying to reignite, the high beams turn on very dimly, and when the light is out, the driver side high beam doesn't light either. Does this give any indication as to whether it is the ballast or bulb? Id like to not start tearing the front bumper off to change the ballast/igniter if I dont have to.

 

Chances are that there's a short in the wiring connections or ground.
You could try a known good bulb, but it's more than likely that moisture has compromised the system.