i've seen this problem with my own unit happen. Good chance its not the fan motor, but the run capacitor for it that gives it a "boost" to run. It probably is a dual capacitor, compressor run and fan run, try replacing it. not expensive. I'm currently working on a system to shut the control system off when this happens, because if you let the compressor run without that condensor fan, you'll burn that puppy right out and require total system replacement. good luck i need to add that this could be dangerous, all power to unit has to be off, existing capacitor has to be discharged, even with power off.