Hi, you need to diagnose whether it is electrical or the fluid pipework that's at fault. I would start by checking the fuse first, then the connectors and the pump. If they check out ok and the pump is operating it sounds like you may have a blockage in the pipework/jets. Compressed air is good for that!
Just a thought here, i have never tried the washers with the roof down? That would be typically un germanic! I cant try that today because the english weather has reared it's head again. :frown: