* The fan motor may be faulty. If the fan motor is not working properly, it will not be able to circulate the air through the condenser coils, which will prevent the unit from cooling properly.
* The fan blade may be damaged. If the fan blade is damaged, it will not be able to move air effectively, which will also prevent the unit from cooling properly.
* The capacitor may be faulty. The capacitor is responsible for starting the fan motor, so if it is faulty, the fan motor will not be able to start.
* There may be a problem with the wiring. If there is a problem with the wiring, the power will not be able to reach the fan motor, which will prevent it from starting.
If you are not comfortable troubleshooting and repairing your AC unit yourself, you should contact a qualified HVAC technician to diagnose and repair the problem.