2014 C300 Electric Radiator Fan Stays Running Full Speed With Engine On

[FSC Trucking]

I have a 2014 Mercedes C300 with the V6. When starting the car the electric radiator fan comes on and gently steps up to full speed. It turns off when the car is turned off.
The car is NOT overheating, and the Air Conditioning operates normally. The car is full of coolant.
I was told by my local dealer that the last one they had (C300) had this same problem. The fix to that car was the HVAC control in the dash.
I ordered one and replaced it. The problem remains.
Here are my questions.
Looking online the so called typical solutions is the A/C pressure switch under the radiator. Or the Coolant Temp sensor in the engine.
This makes no logic to me as the gauge in the dash reads normal coolant temp, and there are no engine codes.
The Air Conditioning functions normally.
What am I missing?

 

[DREAMER NO2]

Could be this ,, but you need to get star readout

 

[alexanderfoti]

100% get it diagnosed, throwing parts is expensive and a matter of luck