Digging deeper and deeper in the engine bay, I found something I don’t really understand. Maybe the esteemed members of the forum can enlighten me.
The refrigiration system has a electronic box that senses if any of the fridge-compressors is running. If so it activates the sea-water pump to push cooling water through the systems. Now this box indicates 12 or 24 volts and the 24 volt LED lights up. So far so good. Now why are the actual pumps (main and spare) 12 volt? And where is the converter that supplies the 12 volt for the pump?
Thank you all for taking the effort to read my query!