I know this post is old but I had the same problem and no one posted a solution. It could of helped me before all the costs! So here is my follow up to this problem....
This is for my situation, let me know if this was correct with yours?
UPDATE: So i finally figured out what was wrong.
The modification shop used some generic HIDs thus shorting out the ballas (?spelling) under the headlight. As explained to me there are two ballases, one on the end of the bulb and one under the headlight. The BMW tech called it a xenon processor.
I took it to BMW and they would not warranty the work so be careful. It ended up costing $1700 with parts and labor. Needless to say I refused to pay for it and the mod shop had to cover the cost.
Apparently this is a common problem when people use generic HIDs. At the time, I took the car into get tinted and the guy upsold me on saying the car would look awesome with some HIDs so I said ok lets do it. Not knowing anything (before I was a member of this forum
) So be careful!!
Thought I'd follow up cause I looked all over the forum for an answer to this problem and found other who had it yet no one posted the solution!"