Product review (5 stars): Buy the thermostat and defrost timer
If your freezer is workIng but your fridge is warm. You need this item!  You should also get Frigidaire 215846604 Defrost Timer. They work together. Save yourself the trial and error headache.  And just replace bother the thermostat and defrost timer. Cheaper then buying a new refrigerator. There are easy walk through tutorials on YouTube. Hope this helps.