Using a volt meter set for 120v ac, touch the fan motor terminals and check for 120 volts.
If voltage is present, replace the fan motor.
If voltage is not present, replace the adaptive defrost control.
I would tell you to take a meter and check the Ohms on the fan motor. However, I have done this a number of times and still had a motor that would not run.
Yes, your compressor relays are good.
Try replacing your filter,especially if it is 6 months or older.