FRIDGE NOT COOLING ON PROPANE

If the flue is hot and your sure it's clean/clear then you may have some a blockage caused by the crystallization of ammonia caused by off level operation. In theory blockage should impact electric operation as well but sometimes you can get temporary blockage and it might be coincidental that you only notice when using propane. Just a thought.

If the check light is on it could possibly be the flue thermocouple, if the check light is not on it could possibly be the lower circuit board. Check on line there should be a repair manual you can read and maybe perform some testing.

I would check to see if flame is going out.

IF you had a blockage in cooling unit it would affect both electric and gas operation......one cooling unit/2 heats sources and blockage is permanent.

Insufficient cooling on gas:
Low gas pressure
Flue baffle out of position
Dirty flue
Dirty burner
Dirty main orifice

You have blue flame........is it centered under flue chamber?
Flue baffle should be 1 7/8" above burner.......too high and not going to get proper heat transfer
Flue tube.....needs to be cleaned......carbon/soot will inhibit proper heat transfer

Poor cooling on gas only is nearly always a too low, poor flame. 1/4 inch flame is not high enough, should be 1 inch at least. When listening you should be able to hear a slight roar noise.

How old is the burner tube? Are the slots rusted out, enlarging the air volume causing a smaller less efficient flame?

thanks for the feedback everyone. i cleaned the flue, some but not too much fell out. took it to a friend who's an rv tech, and found out the propane regulator was bad and oil in one of the propane lines. the is better than before, so now sitting with our fingers crossed to see if that helps. thanks again everyone. happy camping.