I wanted to add my $.02 to this as I just went to dealer to get a new bulb. A mechanic I know there wandered in and said it might be something else. Of course it's BMW. The "Socket" for the bulb had a burnt contact. Apparently the contact board can burn also and then you get into a real mess. My contact board was fine and he found a replacement socket in his tool box (they keep them as they burn up regularly). Tipped the guy as he diagnosed, replaced and comp'ed me a part in like 3 minutes. Hope this helps the next guy !

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'06 X5 3.0l