We don't have that model of refrigerator, but we have had a similar issue. Turns out our problem was a build-up of ice in the freezer that was blocking air from moving from the freezer into the refrigerator portion. Our refrigerator is 12-volt only and generally cools extremely well. But we were camping along the Texas coast and I suppose the heat and high humidity caused the extra ice to form. If I understand correctly, our unit cools the freezer portion first, then blowers circulate that cold air into the refrigerator area. Once it ices up, the cold air can't move to the lower portion.
