Hey Terry, if yours is original to the coach it is gas only. Check the thread Anyone out there with refer as old as mine?
Also, there is a thread on "burping" old refers and some other stuff that might be helpful. Try Burping my Fridge???
and renewing old refrigerators
. I didn't think mine worked either, but found the trailer must be level especially from front to back. Side to side leveling is important, but not as crucial. It's a beautiful thing to see ice from a 46 year old Dometic.
As far as replacement, I'll have to punt that to someone else in the know.