If it fails only on electric then it COULD be something simple like the electric heater. Hard to say though if the LP mode never worked. The "check" light simply tells you that the gas burner did not light. It will make a set number of attempts (usually about 10 minutes worth) then go into lock out mode. Once you turn it off then back on again, it will start the lighting sequence again. If it hasn't been using LP gas for quite some time it may be difficult to light and take a number of attempts before it gets all of the air out of the lines. It is POSSIBLE that if the gas would light it may cool in LP mode. It does require heat from ONE source or the other to cool. I'd start by checking or having checked, the electric heating element. It could also be the thermostat causing the problem. The thermostat also is a 12 volt item so has a small fuse in the line (usually inside the control box) so checking that fuse would also be a good idea but usually that would go out suddenly. USUALLY when the fridge looses it's coolant you see a yellow sulfur looking powder from the ammonia loss and the smell is easily noticeable also.
