AC Thermostat Bypass - Short Cycle

Good idea to take a look at the EVAP coil just to eliminate it's freezing up as a possibility, but I doubt it if it's hot in the trailer.

If the voltage is good but the compressor is cutting out and it's not the stat or the Easystart then it's possible it's the compressor thermal overload switch, especially since its happening more when it's really hot. Do a search for the Dometic manual, there is a schematic toward the end that shows where the switch is connected. You should be able to test it with a voltmeter with someone inside turning on the a/c.

Probably the switch will close again pretty quickly as it cools, it's just a little poppet sensor. If it's open when you get the short cycle then either it's bad or it's doing its job and your compressor is overheating. If it's bad then it's a cheap fix but if the compressor is overheating and the condenser coils are clean then you have $$$ issues.

Electrical Demons!!

I thought you'd already checked the line voltage earlier? Where did you check it and was the a/c on when you did it? There can be a significant resistive drop between the home panel and the a/c so you need to measure at the a/c itself while it's running.

I don't know of anything other than low line voltage to the a/c compressor that would cause it to overheat that a bad cord or connector could cause without also tripping a breaker.

I've overheated a connectorsll before running the a/c from a 15A circuit without tripping a breaker. The a/c takes so close to the breaker trip point that it's kinda a race between what will overheat first. That's why it's so much better to put in a 30A dedicated circuit for the trailer.

Just to followup before HVAC tech arrives. I contacted local HVAC company. They reluctantly agreed to send a tech with no guarantee. I explained I just need someone to look at it and give me an opinion.