Sorry to hear you're still having trouble.
T.J., the guy at rvmobile.com, rebuilt the cooling unit for our fridge--not cheap, but good workmanship. He was kind enough to talk me through the whole thing, although if it's on his website, he's not slow to tell you to go read it first. Call him if your problem's not on his site. If one part of the fridge works, I can't see why the whole thing won't--isn't it one cooling unit?
After I reinstalled the cooling unit, I was able to test our fridge in the shop with a barbeque propane bottle and regulator before I reinstalled it in the trailer. Ran it on both gas and electric, and it worked fine.
I had never worked on a gas/electric fridge before in my life, and T.J. got me through it. He has my recommendation!