Repairing an air cooler fan motor can be challenging and may require advanced technical skills. However, you can try the following steps:

1. Unplug the air cooler from the power source.
2. Remove the screws or clips that are holding the fan grille in place.
3. Take off the fan grille and set it aside.
4. Locate the motor that powers the fan blades.
5. Check the motor for any signs of damage, such as a broken shaft, worn bearings, or burnt wiring.
6. If the motor is damaged, it may need to be replaced. You can contact the manufacturer for a replacement motor or purchase one from a hardware store.
7. If the motor is not damaged, check the wiring connections to ensure they are secure and connected correctly.
8. Test the motor by plugging in the air cooler and turning it on. Listen for any unusual sounds or vibrations coming from the motor.
9. If the motor is still not working correctly, it may require professional repairs or replacement.

It's worth noting that repairing electrical appliances can be dangerous and may pose risks of electric shock.it may be best to hire a professional from Locals4u for assistance or contact the manufacturer for guidance on repairing the air cooler fan motor.