We've experienced this same problem. We did have a blown glass fuse in the outside fuse box, but that did not solve our problem. Like your's our fridge was working on electric, but when we cleaned it out and parked it in the driveway - it didn't work on electric the next time we went on a trip - a few weeks later. Get's nice and cold on Propane though.
What I feel I have narrowed our problem down to is the refrigerator heating element. It's a relatively low cost item and will be the next item that I try out. You can find some different ones here on ebay
Let us know what you find.