The troubleshooting hints suggested the temp sensor was a probable cause, so I bought two sensors. I replaced the sensor that is on the wall between the frig and freezer, but it did not solve the problem. I took apart the entire back of the frig compartment and after a lot of looking, discovered there was a second temp sensor that is tie-wrapped to the backside of the cooling coils in the frig compartment. It is easy to find by following the white wires that attach the sensor. The sensor itself was inserted into a form-fitting heat sink. I pushed the sensor out of the heat-sink, and pushed the new sensor into it and spiced the wires with some crimp lugs. The old sensor had a molded gasket that seals the wires, but the new one did not have that. I cut the gasket off the old one carefully by slicing it like a hot-dog bun, removed it, and wrapped it onto the new one's wires and it worked perfectly. I suppose you could also use silicone to seal it. After putting it all together it worked perfectly again. While you are doing all this work to disassemble the frig compartment, you probably want to replace the drain trough assembly. Mine has already rusted through once, and I had to replace it. It's a bad design if it rusts through.