Hello everyone! I have a terrible headache caused by my 2013 2.0 petrol X351, VIN: SAJAA12M3DPV40996.

To cut straight to the point, the radiator fan doesn't work as it should, turning on just when the coolant temperature reaches 102°C at just under 20% of its capacity.

​​​​​​I tested all components and they work fine:
- the fan works properly, turning at the correct speed according to the modulating signal it receives, all the way up to 100%.
- the coolant sensor (it only has one) works fine.
- the compressor clutch is working properly, too. It engages and disengages as it should; when on it slightly increases the modulating signal for the fan but not enough to spin it (7.451% up from 7.093% when off; it needs minimum 12% to start).
- there is signal from the transmission module as the signal increases slightly when the car moves faster than 20km/h.
- the refrigerant level and pressure are correct.
- refrigerant pressure sensor is also good.
- the evaporator sensor is also working.

After monitoring in real time all those parameters, I found out that the evaporator temperature is not taken into account by the ECU when sending the modulation signal to the fan. As a result, because the heat exchange at the condenser level is faulty, the evaporator is warm all the time (more than 20°C) instead of 3°C which is the normal temp (as found in all the other cars that I tested).

I found out that in other cars, the evap temp is the parameter that keeps the fan going at about 25%, which is enough to keep it at 3 degrees in normal operating conditions in mild winter weather.

When the fan is in test mode and it spins at high speed, eventually the evap temp goes to normal temperature too.

​​​​​​So, my guess is that there is a software issue which causes a miscommunication between the evap temp sensor and the radiator fan which, as I said, both work and both communicate with the ECU since they can be read with the obd tester.

​​​So, besides going to the dealership (where I had horrendous experience before - incompetence, theft, miscommunication), what else should I look for?

​​​​​​I'm thinking that because the 2.0 engine is quite rare on the XJ, there might be a specific coding that I need to perform or that there might be a software update which I missed out - the car was serviced by the dealership until 2019 when it got out of warranty but I don't remember them saying anything about doing software updates besides one that was performed in 2014 after a steering valve replacement.

I would really appreciate your help!