2 of 3 units not working correctly. Does not matter the mode (Auto/Hi/Lo). Example - Low Speed selected. Turn on the AC Unit because its hot outside. The fan will come on / compressor will kick on and it may run 5 minutes or 30 minutes. Temperature is not the driving factor because it is Tucson AZ and hot meaning that it is not shutting off because it has reached its requested temp. Basically - I have to turn it off wait a few minutes and then turn it back on and repeat to keep the room cool. Oh and sometimes it will come on low - then turn off and shift to hi speed fan for a short period and then turn back to low or off. Any ideas? Thermostat or Control Board?