Disconnect the plug from the thermal switch.
Short-circuit the two contacts of the plug with a piece of insulated wire. If the fan starts working, then the thermal switch, which in this case interrupts the current circuit, is faulty.
To continue moving, place a jumper between the contacts. In this case, the radiator fan will work constantly.
To prevent loose wires from causing short circuits, insulate them with electrical tape or scotch tape.
If bypassing the thermal switch does not help, apply battery voltage directly to the motor terminals.
If the motor does not rotate, then the motor itself is faulty. In this case, it is necessary to replace the electric motor.
(The basis of the material is information from the website: HYUNDAIBOOK.ru)
Note: If there is a jumper, it must be disconnected after the end of the movement, otherwise the fan motor will run until the battery is discharged.