(Unsure of age of fridge as we got it used) .... Original symptoms: Freezer cold, fridge too warm. Identified defrost problem (evaporator coils completely frozen, heater burned out). Replaced heater & defrost thermostat. Completely defrosted freezer, let run. Defrost seems to be working now but fridge still hovers between 47* & 52*. Replaced both thermistors in freezer. The original evaporator thermistor definitely tested bad. Tested all thermistors after replacing those two... Confused by results: First reading from newly installed evaporator thermistor was 16.4 (in ice), but only 14.86 thereafter. Freezer thermistor tested at 14.08 (in ice water), and fresh food thermistor tests at 13.76. Freezer seems fine now, appears to be functioning normally. Evaporator fan seems to run fine. However, very little air flows to fridge side through the vent. We actually removed the vent assembly this morning to allow free flow of air to fridge, but still not very cold in fridge side. The vent is simply a thin piece of plastic sheeting hangin from assembly - does not appear to be electronically controlled (as I've read that some open and close based on temp) -only other thing attached to the assembly is light bulb (and thermistor). Fridge temp is starting to go down now (currently down to 42*) - but why won't it cool with it in place? There are no obstructions..... Where to go from here? Are thermistors in ok range (supposed to test @16.3? If not -how to explain?) Replace fresh food thermistor? Only other option seems to be main board... Don't know how to check that. We did check defrost system for continuity on main board also = fine. Are we missing something? There are no strange noises, compressor runs as does compressor fan. Thanks for help!!