Have been working on my GE side by side fridge for a while now due to a so called "technician" coming over an replacing the main control board ($200) without troubleshooting anything. So now after discovering (thanks barberofcivil) there is no hold button to initiate diagnostic testing as stated in the manual (it has a place on the board where it used to be on earlier models), I have now diagnosed the actual issue.
The problem is, during the defrost cycle the temperature in both the fresh and freezer sides gets too high (35F in the freezer and 50F in the fridge). The rest of the cycle appears to run correctly.
The temperatures stay within spec during normal operation. Tested the temperature thermistors and they are within spec. I have thoroughly read all of the tech manuals and it appears to me that the heater / thermostat is getting too hot and then shutting off.
So with this limited information, will replacing the heater and thermostat solve the problem, or am I missing something else here? Any help is very much appreciated!!