The Dometic Thermostats are known to be glichy. It's possible that the Tstat isn't root cause of your current symptoms but it could well be. One thing to try is to remove the cover and then operate it. May or may not help but some have said that it works better. If it does then you know it's the Tstat.
As Bartman said, maybe just bite the bullet, as many of us have, and get the MicroAir Thermostat. A little spendy, sure, but I haven't regretted getting one. So much better and easier to use.
https://www.microair.net/collections...c-replacements
Welcome to the forum! Let us know how it goes.
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Jeff & Sandi (and Teddy - 7lb Schnorkie)
2018 Montana HC 305RL / HW Progressive EMS
2015 RAM 3500 Laramie Longhorn Crew Cab 4x4 DRW / Demco Recon Hitch on RAM Puck Ball