From the pictures there is a lot of **** and debris around the flue or heater area. If this were mine I would start by giving this a good cleaning. Start at the top and check the roof vent to make sure it is clean and free of anything that would bloc...
I have a 96 Bronco 1200 and I can tell you that even on propane that fridge is marginal at best. The problem is with the side ventilation on the rear of the fridge. Just doesn't work the best. I replaced the cooling unit on mine and added three muffi...