I ordered a new set of defrost heaters and a defrost timer (as a spare) from AppliancePartsPros.com and the parts arrived quickly. I removed the back panel, manually defrosted the cooling coils with a hair dryer and installed the new heater assembly. The fridge section as well as the freezer are both holding temp well now. 0 degree freezer, 38 degree fridge. The hardest part of the whole repair was taking everything out of the freezer to get to the back panel. I'm lucky enough to have a free standing freezer to put the frozen foods in while I was repairing the fridge.