Hello everyone and many thanks for your feedback.

To answer ZULU 95's question, yes the fan is working immediately after starting the engine and the air is going on my feet and on the rear. After a few minutes, A/C works normally (my only problem is these few minutes without A/C in a very hot country during spring and summer).

YES it is blowing somewhere (feets and rear) and it really looks like a problem with the circuit that decides where the air blows, it blows but not where it is important, the main front vents.

I'll change the FSR and let you know