W204 rear blind

[Millarcontracts]

I was wounding if any one has any idea what would be wrong It goes up find but when it goes down it doesn't stop and clicks really loud
http://i724.photobucket.com/albums/...484A06B-6618-000005CB1C45E4F9_zpsa8ff32d4.mp4
this is a link to the video of what happens
Any help would be great

 

[Diesel Benz]

Its not clear from the video but does the blind close further on one side compared to the other? The control unit must assume that the blind has not gone fully down. Either something is blocking it or the gears are broken. Or it could be something completely different.

 

[Millarcontracts]

Does the blind have a switch that that it hits when goes down or how does it know when to stop?

 

[Diesel Benz]

No, there does not appear to be any limit switch. The end position of the blind is detected from an increased current at the drive motor.

 

[Millarcontracts]

No, there does not appear to be any limit switch. The end position of the blind is detected from an increased current at the drive motor.

That sounds complicated I think I will just not touch that button!!