Had the same problem. Took it to the shop and was told that there is a problem with the microswitch and the mirror replacement unit cost ~US$500 (excluding the cover and mirror which will be use back). I thought, what the heck, it is a long Easter Weekend, I might as well have a crack at it. Got the cover out and gave the internals a good clean - it was very dusty. I suspect the shop did not bother to check properly. The microswitch was perfectly alright. After some try and error, I got it working intermittently without having to bend the metal piece on the microswitch. Eventually, slipping a piece of felt to hold/tighten the microswitch in place fixed the problem. I think the design is bad in the sense that the tolerance is so refine as to either render the mirror working or not working . Everything works now .

My X5 http://tur-www1.massey.ac.nz/~cteo/X5_1.JPG . I know, just another X5 but this one has travel a fair distance from USA to get here in The Land of the Long White Cloud.