Hi Paolo,
Tonight I had a call with Klaus as well. We talked about a lot of technical details and I'd say you can rely on him and his recommendations. But don't trust the BMW guys, same here in Germany. They only try around and have to make cash without any experiences :-(
The relays have to be replaced all 5 years to avoid melted pumps, but that it is not the source of your problem. But do it immediately.
The results of my analysis were posted in the German Z4 forum. I made the recommendation to get these two relays replaced let’s say every 5 years.
https://www.zroadster.com/forum/thre...-jahre.133521/
Thanks to Google Translate you can read it in English as well:
https://translate.google.com/transla...ahre.133521%2F
To use the 4th selenoid you also need a newer CTM (cabrio top module) to manage this fourth channel.
Opening while driving is an option you can activate by carly, but I've mounted an additional module from XCarStyle here in Germany. With this I can open/close it while driving and much more important, I can open AND close the roof remotely by the key.
Details about the E89 roof construction:
https://www.zroadster.com/forum/thre.../#post-2773183
With Roofmotors.uk.com I made very bad experiences:
At first he delivered a refurbished pump that did not work. Then there was a huge delay to refund.
My 2nd order got cancelled after I've paid the money and then we run into the same refunding problem. Just keep away of it.
The new harness from BMW (about 1 k€ in Germany) always has the additional wires for the 4th selenoid. If it's not required you can leave it unplugged.
Each side has a lenght of about 3m and is connected in the middle at the hydraulic pump's position. It contains the 2x6 hydraulic hoses as well as all wires for micro switches and hall sensors, all connectors and even the plugs for the two salmon relays.