The radiator fans can be inoperative due to bad relay, wiring issues, bad motor or faulty coolant temperature sensor.
Since you have already ruled out the fan and the relay and the wiring. It could be a faulty coolant temperature sensor. The coolant temperature sensor that sends the signal to the ECM, which triggers the fan to come on.
Bad sensor will be unable to send correct signal and that will lead to an inoperative fan.
The coolant temperature sensor is located on the right-hand side of the engine (see picture below).
Please let me know if you have any questions.
Images (Click to enlarge)
Tuesday, December 14th, 2021 AT 2:34 PM