Thought I'd ask this before I go poking around.

Driver's side HID is going, but not sure if it's the bulb or ballast.

The bulb will come on most of the time, but it is noticeably less bright. It will not remain on for long periods and eventually extinguishes. Turning headlight switch off/on will usually re-ignite.

thoughts?

Perhaps unrelated, the driver's side parking/driving light is also out and will not turn on.

 

could try switching your bulbs and see if that helps. If it does then it's the bulb, if not, then i imagine it'd be the ballast

 

That's what I'll probably end up doing.. Just never had a HID go out on any car so I don't know what the symptoms are vs a dying ballast.