Stops running thermostat

SOURCE: Coleman RV roof air

I think you have a high pressure switch that has tripped. open up the case and look for a switch connected to the line with a resettable button in the case it is not resettable you will have to have a professional replace it. If you are able to reset it make sure to clean the condensing coil on the top side before running it again as most likley this is what may have caused it to trip.

SOURCE: Compressor will not come on. Fan runs great.

I fixed it. I had a dirty connection on the starter relay for the compressor. Thanks again for the help.

SOURCE: DuoTherm compressor starts but will not continue to run

check condenser fan if running. it will make compressor comes on and off if broken

SOURCE: RV air conditioner. Compressor running, fan stops before cool

The fan motor is getting hot and going off on the internal overload in the motor.
This is caused by either a low voltage, a bad capacitor, or tight or dry bearings in the motor.
To check the bearings turn the power off to the unit, then spin the fan blade if it spins freely then the bearings are ok.
To check the capacitor you will need some kind of tester or you can buy a capacitor and replace it, that's what a lot of people do. They usually don't cost very much.
To check the voltage you will need a voltmeter and measure the volts at the unit.

SOURCE: Compressor doesnt come on in a dometic duotherm

If this is a wall thermostat controlled unit, then check to make sure that you have power coming from the yellow wire on the thermostat when it is placed in the Cool/Auto High mode. If you do not have power at the yellow wire, then you have a bad thermostat. If you do have power, then remove the control unit from the inside of the AC and see if you have power at the Y terminal there. If so, when you turn the thermostat to cool, can you hear a relay clicking in the box? If not, then you have a bad control box. If the relay is clicking, you need to check the power at the compressor relay on the board. It has a black wire to one side and a purple (or blue) wire on the outgoing side. Check to see if you have 120V on the blue wire when the tstat is set to High/Cool. If not, then you need to bypass the freeze switch to make sure that is not the problem. If you do, then you need to go upstairs and check the start capacitor for OK. It is located in the side compartment of the upper unit, it has a small black relay on the top called a PTCR. These often burn out and will cause the compressor not to work. If that is fine, then you go to the top of the compressor to the thermal overload switch. See if you have power at both sides, if so, then you have a bad compressor. If not, then the overload switch is open and not allowing power to the compressor.