| hey guys im having the same problem, i spoke to my BMW dealer who needs to hook it up to the Diagnostic's as they beleive it is a hyraulic pump problem, ive done some homework on the internet and have found that it is a major problem if this is the cause. £2000 i noticed in one case as the labour charge involved in removing and refitting the roof is sky high!, appartently water damage is cause to the pump and a gasket is required to stop this in future, other means of fault were micro switches... i believe there is a viewing resivoir for the hydraulic fluid in the boot/trunk but cannont find it.
if any body has a good discription of images, of where to locate or other possible causes please let me know!
Many thanks guys as im gutted about this problem and potential cost!!!!
Matt | 
