Thanks for your reply!

When checking more closely, I see that actually only one comes out at all
now, and it stays out. No spraying. Then, when I press this one in without
pressing the other one too, the other one comes out - and goes in again if I
pull the first one out...   :^)  When pressed in together manually, they
finally spray.

But to get to do something with the mechanism it looks to me as if one has
to remove the whole bumper?

And to get access to the hose at the bottom of the wash reservoir under the
bonnet it looks as though you have to remove lots of stuff there too?

Anyway, do you think the hose can just be pinched off to simply set the
whole lamp wash out of use? I would concider this as a solution, I mean, I
am able to wash my head lights manually  ;^)  Or would this cause too much
pressure to the hoses for the windscreen-vipers so that they flip off or
something??

Grateful for any ideas!

Gunnar