Initial symptoms, the refrigerator was running nearly constantly, and I noticed frost inside packages in the freezer. It turns out it was periodically getting warm, Then re-freezing. At one point it went up to 40F, and that's when I discovered this was a real problem (my wife had been complaining about the frost inside packages for months, I should have listened sooner). I tracked this with a recording thermometer. The compressor and condenser coils were all clean, so I knew this wasn't the problem. I narrowed it down to the freezer defrost thermostat (sensor clipped to freezer evaporator) and freezer temperature control (looks like a length of wire running across the back of the freezer above evap coils). I also noted these are among the most common parts purchased from AppliancePartsPros.com, for this model, So it made sense one of them had failed. Since they weren't very expensive I changed both, and since then the freezer and reefer temps have held steady and the compressor is now cycling normally.