On the pump itself, looks like a T, open the valve fully until it stops and then supposedly the roof can be operated by hand, incase say the pump should ever fail.

By the way aswell, yours being a cabrio, they have the most expensive fuse boxes of them all, about £700-£800 IIRC and they are specific to that model only from what i know.

Would be in your best interests to check the part numbers on the fuse boxes.