Weather King question?

Question

We have had this unit for about 5 years or so--since day one we have had problems with it. We had the compressor replaced and it heat good this winter now we turn on the cool and it runs cold for awhile and then it starts shooting out warm air. Outside the fan has stopped running and it making funny squealing sounds. You can shut off the whole unit and then it will take awhile before you can get it to start back up. Had the guy come out that installed it--he thought that it might be the fan motor so he replaced the fan--still does the same thing. Any ideas?? He thought that it might be the circuit board?? Could this be it? Any other ideas on what it could be?? Getting tired of messing with it & not having heating/cooling.
Thanks, Kay