Yup, what RivverCityBrewer said. I just resurrected a spare I had in the shed for 3 years or so. The fan that circulates the air died, so the freezer was fine, but fridge section was warm. $65 later a new fan and its a happy camper. Now to build the temp control. The fridge air gets its cold from the freezer air.
(though dual compressor fridges aren't that expensive, mine wasn't more then $600 I think)