This is the reed relay. I think that is the same as used in the 4000 series two. I have found a possible solution but with a different form factor : a MEDER STANDEX DIP12 - 2A72-21L. The existing one has on one site 2 and 4 connections on the other site. On the site with 4 leads, the middle 2 are de reed contacts (OUT), the outer wires are the coil for 12V. On the other site are 2 leads - these are the reed contacts (IN). So that is solved. Now testing the new - will come back in 5 days (Covid-19 delay for delivering something in Europe).