I guess if you're trying to run the fridge on gas, you should have some heat coming out of the vent stack. No heat--no coolee.
These absorption fridges are cantankerous, too. Park the trailer out of level significantly once and crystallization will start happening in the coolant tubes. I've read where others have slammed the heating unit with a board or taken them out and lightly dropped them upside down to try a fix. But if you have no flame or the electric element doesn't work, you have other problems. Personally, what I did was replace the old absorption unit with a small residential 120V fridge. It is much less problematic but I did a lot of upgrading like solar and batteries with inverter to use it boondocking.
If I totalled the costs between a new absorption fridge and the whole solar upgrade, I believe it would be a wash. The solar also runs everything else, though.
