I had a 1976 Dodge motorhome. My Fridge had the instructions right on it to run on propane. Mine, you had to pull out a knop then keep pushing/pumping another until the pilot light would turn on. There was a glass window to look through to see it lit. I loved running on propane and drove with it on. I have read where you can run your fridge on a 20 gallon propane tank up to 30 days. Very economical. I thought it kept the fridge more cold than electric.
If you have trouble lighting the fridge pilot, light a stove top burner for about 5 minutes then turn off. This helps open up the propane gas lines.
I never ran mine on electric or 12 volt (living quarters battery). I mostly dry camped. (No water or electricity)
Make sure you fill your gasoline tank first so you do not have to worry about turning off the propane when filling up.
Note: Everyone has their own opinion concerning driving with propane on. Do your research. (Yes, I am covering my butt -
)