I ordered the Defrost Thermostat, Temperature Sensor, and Defrost Heater. Unplugged fridge. Took the back panel of the freezer off and it looked like someone packed snow in the coils. Melted all of it with a heat gun. Didn't realize my fridge/freezer has a total of three temp sensors. I ordered one. I googled how to test sensors with a multi-meter. thought it was going to be difficult but quite easy to test. Have thermometer in the fridge at the time of testing so you know the temp and the corresponding chart you can find online that tells you what the OHM reading should be for the sensor temp. Mine were all good but decided to replace the temp sensor at the top of the freezer since I had already bought the part. Same thing with the Defrost Thermostat. Once I removed the Defrost heater I could easily see it was bad. Instead of a clear heater tube with a filament inside it was black. Kind of like a burned-out light bulb. Videos on this web site very good for learning about installing these individual parts. Put everything together and plugged the fridge back in. The compressor/fan did not kick in immediately so I thought I did something wrong. But in about 5-10 minutes everything came on. In about an hour and a half freezer, temp went from 70 to 50 degrees. After so many hours temps returned to normal.