How to Troubleshoot & Replace Ge AP3185407 / WR55X10025 Refrigerator Temperature Sensor

Looked up what on could be the problems on the internet and I found appliance parts pros. Filled out the necessary form out to get what parts I might need. The website also recommended other parts that I might need as well to fix the problem. Also the website had videos explain how to disassemble and reassemble. The issue you have with your appliance, which makes it easier. To help solve the problem. 

Removed cover in back of freezer compartment, replaced temperature sensor and defrost thermostat per online instruction. Generally went as described but my appliance was slightly different than one used in instructions. Defrost cycle now working correctly. Apparently when the part fails, it defaults into a 45 minute defrost cycle which is too long for my appliance. 

I replaced all sensors and defrost thermostat's, defrost heater, fan motor 

My husband replaced the defrost thermostat and the refrigerator defrost heater and bracket assembly. 

Replaced all three thermistor 

Replace defrost thermostat 

Condenser fan was bad and not spinning. Replacing this helped the fridge to run less frequently. Still had a problem of the freezer getting too warm during defrost cycles. Replaced the temp sensor at the top of the evaporator, and instead of seeing peak temps of 50 degF I'm now seeing 8 degF max. I put my meter across the old thermistor and in ice water it was reading 35kohm, which according to the table is around 5 degF. So the thermistor was thinking it was 25+ degrees colder than it actually was, which explains the defrost cycle behavior. 

Replaced the defrost heater, defrost thermostat, and the temperature sensor. 

Replaced temperature senor 

Followed your video on how to replace parts. Old defrost heater was still good but quite warn so I replaced it anyway. Replacing the temp sensor fixed the problem. Verified evaporator fan still worked. I replaced it a couple years ago.