[scottz]

I feel your frustration. I have been fighting similar AC issues for three years. My units (one or both), when the fan is on auto, will intermittently shut down and not start back up until I manually reset. If I keep the fans on high, no problems, just constant noise. I believe my units are freezing up.

It has been to three dealers and the Dometic guys at national looked at it. Unfortunately, the problem is intermittent and, of course, never occurs when they are looking at it. Thermostats & face plates replaced a couple of times; return ducts opened up; all the usual stuff.

I might have solved the problem with mine. Difficult to tell since we don't use AC that often and I think other factors such as humidity are in play.

I finally pulled lifted the units off the roof and found they had not been mounted over the holes in the roof properly. I suspect a portion of the cold air output was going directly into the return side and freezing the unit up. Keeping the fan on high keeps air moving and prevents the problem. Anyway, that is my theory and not sure if it helps with your problem.

Here is a link to a thread with more details and photos.

https://www.montanaowners.com/forums...ad.php?t=75245