Aircon Auxiliary Fan

[HAGGAI]

Hi, I changed my aux fan when aircon blowing hot air. They 1st used OEM fan but as it was not working properly, they changed to original part, costing $200 more! (total cost $700). Before I took my car, it was on full blast and fan was rotating/working. Been using for several days now and while aircon is quiet and cool, I did not see the fan rotating anymore when I start the engine. The fan used to start by itself and stop momentarily depending, I suppose, on heat of engine.

Any advice/sharing would be appreciated. Tks.

Regards