This helps me a lot...

This should help you understand how absorption refrigeration works. Both tubes will be hot. The one is the chimney for exhausting combustion gasses. The other, connected to the fins, is the coolant. As you can see, as it exits the boiler, it is hot. The fins cool it so the gas condenses to a liquid. That liquid goes to the evaporator section where the cooling happens.  Then it goes to the refrigerator section to cool that. Finally, it flows into a collecting tank. The liquid goes to the boiler, starting the whole process again.

Question.   There are 2 black tubes coming out of the top of the baffle chimney.  One is a vest with a T for venting and this tube is very hot when on propane.  The other tube leading to the fins, is it supposed to be hot or cool or ?    Fridge will not cool on LP.....Any suggestions appreciated..

Our original Dometic fridge lasted 10 years, was replaced with the same model and make 3+ years ago.

A few things I have had success with will be shared, even when ambient temp is at 92 fridge temp is 36.

1) bug screens over both 2 vents to keep spiders, insects, bees out.

2) move the bi-metal switch (located by 2 red wires leading to it) to within 1.5-2" away from heat stack chimney.  switch is usually located between the 6th and 7th fin on the cooling radiator-move to the right.

3) add a couple muffin fans just under the upper radiator and install a baffle around them to direct heat flow over the fins and out the rear of the fridge vent.  PM me for pictures or further information.

4) ideally park so that the rear of fridge faces N, 2nd choice would be E.  Avoid south and west exposures any time temperature is warm or hot.