Number5 said:Ive replaced these on a roof before.. They can twist and chew the end sockets off.
The problem arises if the latching sensor is broken causing them to keep spinning even though the latch is fully engaged.. They are £70 each at BMW but I have a pair along with other most of the other front equipment on ebay.
Let me know if you struggle to source them and want mine or even want me to do it. You ideally have to peel the canvas back off the roof in order to access them from the top.