Cooling problems

SO I have a Dometic Rooftop mounted AC unit, run by thermostat. Yesterday night I had it set to Auto and 72. In the middle of the night I woke up hot. I then set it to low/manual, compressor came on and ran for about 20 minutes, then compressor and fan both shut down simultaneously. I fiddled with it some and was able to get it to come on again and run for some time before it shut down again and showed and E1 error code.

in the morning I went to my dealer and they said the code meant a bad circuit board. I replaced the board and t-stat yesterday about noon. Unit came on and ran continuously until about 8:00 last night when it finally caught up with itself ( 95 here yesterday)and shut down, but would not come back on as camper heated up. Same thing! I got it to come on low/manual for about 20 minutes and it all shut down. Then I set it to high/manual and it ran fine all night, with the compressor cycling normally as needed.

Had to come into firehouse for a shift today so just set it to 74 on Auto and came to work. Figured I know if was working at all when I get back to lake in the morning.

It seems to run and cool normally, the trick is to get it to cycle properly; any thoughts or suggestions before sending it into shop???