Our Dometic fridge is a continuous run fridge in an A-frame. Performance was very inconsistent until I made some changes to the original factory installation.
First step was to get air flow from the bottom air intake through the cooling coils and out the top exhaust vent. Because of the folding nature of the A-frame, there was only 27" from the bottom intake to the top exhaust vent. Not really enough to create a decent chimney effect, especially with the Dometic vents, which couldn't pass wind in a hurricane (actually they do alright at 50+ MPH while being towed, but we don't normally have that when camping). There was also considerable dead air space above the exhaust vent, where hot air collected but did not exhaust.
Using Reflectix, I closed off the dead space at the top and sides of the compartment, and tried to smooth the air path through the compartment. This helped, but did not consistently solve the problem of not getting enough air through the cooing coils.
Following the lead of some other A-frame owners, I tie-wrapped a 12V computer cooling fan to the exhaust vent. Between the Reflectix and the cooling fan, my fridge runs on much lower AC and propane settings while easily maintaining high 30s inside the fridge. I put a switch in the fan power lead to turn it off when towing (not needed) or cold weather camping (again not needed). Otherwise, the fan runs full time, moving 420CFM at 70 milliamps.
I would say your fans not running is a bad sign. But the fact that's it's always been erratic suggests you have an airflow problem from the get-go.
just my experiences
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time