What are the possible defects when the IR remote control no longer works (or better, never worked for years)?
I'm gonna shut out empty batteries. A trial with new button cells and a learning process was started a long time ago! Since both keys do not work, I can believe less in a defect of both keys!
Is there a single fuse that is only there for the FB? No, isn't it?
Can both receivers be defective in the B columns?
Is there a controller for the IR-FB? If so, where? Under the back bench? Or is it just the ZV pump? Is the control unit of the FB integrated (if available)? I got something in my head!
Let's shoot.

Thank you!