All the fridge repair videos I have seen demonstrate how a fridge with a damper works – in which case all the cooling happens in the freezer and a vent with configurable damper diverts some cold air to the fridge. Perhaps that is a US design.
European fridges are apparently different. The fridge and freezer are separate with no interconnecting vent. No fans either. The freezer is surrounded with coils embedded in the surface panels. The fridge has a plate with embedded tube for coolant. I am surprised that a plate the size of a large dinner plate/platter is big enough to cool the whole fridge.
The plate also has a tube in a loop of tubing that is not embedded into the plate but against it. The two ends of the tube join into a molding with 3 wires going to the thermostat (one of which is a ground wire). What is that thing?
There is a separate wire that goes to the thermostat. I think that is the probe that actually reacts to the temp.
I couldn’t easily send pics because the plate does not come off. I can barely pry it to get an eyeball behind it. I think everytime I bend the plate to see behind it I probably bend the tubes carrying coolant (not good).
That could be the heater for the self defrost, if this refrigerator has that feature. It would be connected to a thermostat to prevent overheating, and would be under or against the cold plate.
Fairly certain this is the answer. Cheaper fridges seem to have this kind of design in my experience
One thing to note is that only some fridges don’t have vents. Ones advertising “no frost” or “low frost” as a feature do have vents that serve to keep the air circulating and remove moisture from the air. They might still follow a different approach from American fridges, though.
Unless you have identified another set of wires between the thermostat and the evaporator coil, then I would assume the “extra” tubing is just part of the coil. The coil has a solenoid valve so the thermostat can control the flow of refrigerant.
