I detailed some of the things I went through with getting the fridge to work well in my A-frame in this thread:
https://www.forestriverforums.com/fo...-104964-4.html
1st question: did the fridge ever work well on propane? If yes, then you likely have a problem with insufficient flame for various reasons. If it never has, or you don't know, then you may well have an installation issue.
For trouble shooting you need to know actual fridge temps. I use a $10 wireless outdoor thermometer from Walmart. I put the outdoor sensor in the fridge, and the receiver display either in the tow vehicle, or inside the camper when camping. This way I know whether the fridge is cooling - and I know when we have to throw food out because fridge wasn't working well enough. I used the thermometer to determine the propane flame was blowing out when I was towing our smaller A-frame, so I had to switch to 12V operation when towing. On the larger A-frame, propane will automatically relight if/when it blows out, so I don't need 12V mode.
To work well, an absorption fridge has to have a flow of cooling air across the coils. Forest River fridge installations often leave a lot to be desired, resulting in the flow of cooling air not being sufficient. Download the Dometic manual for your model fridge, and compare the installation guidelines/requirements with what you actually have.
After fixing the various installation issues, I have found the Dometic fridges I've had in my 2 A-frames work consistently. Even in a hot garage, the fridge will pull down to below 40 overnight. I do pre-cool items I load in when starting the fridge.
For our last trip, I added 2 120mm computer case fans ($14 each) to blow hot air out the exhaust vent. I put them on a manual switch rather than thermostatic control. The existing fan just below the baffle never turned on until the compartment was really hot, was noisy when it came on, and didn't move enough air anyway. The computer case exhaust fans really cemented performance on propane - to the point where I had to back off the setting from 5 (max cool) to 4 to avoid freezing eggs and beverages. I also added the Camco fridge interior fan ($20) that runs on D-cells. The interior fan made a big difference in reducing recovery time after the fridge had been opened and all the cold air spilled out.
just our experiences
Fred W
2019 Flagstaff T21TBHW A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time