The fan in your car stopped working except when set to the highest setting.
Car heater fan only runs on high.
If the resistor block tests out good and you don t have any fan speed or a slow fan speed for all speeds you can assume that the blower motor is at fault since everything else has tested out ok.
If it doesn t light up or you only have a high fan speed then your resistor block needs replacement since it is bypassed on high speed.
Though having only one fan speed usually indicates a bad blower resistor a diligent mechanic at a repair shop will test the resistor fan switch and connections to the motor to make sure nothing.