Diagnosing thermistor problems in your JennAir bottom-mount refrigerator
If the fresh food section of your refrigerator isn’t cooling properly, you could have a problem with the appliance’s thermistor or temperature sensor. The electronic control board monitors the thermistor and controls the refrigerator temperature based on thermistor signals. A broken thermistor could send the wrong information to the control board, resulting in a refrigerator temperature that’s too cold or not cold enough.
Check the thermistor resistance. For safety, unplug the refrigerator. Remove the thermistor cover to access the thermistor. Examine the thermistor's wire harness for damage or loose connections. If the wiring harness looks okay, check the resistance of the thermistor using a multimeter. Remove the thermistor and put the meter leads on the two white wires. The tech sheet for your refrigerator includes a temperature/resistance chart for the thermistor. You can usually find the tech sheet inside the refrigerator, stored behind the bottom front grill. Refer to this chart for the expected resistance readings for your model.
You'll need to replace the thermistor if its resistance doesn't match the expected resistance on the temperature/resistance chart.
If thermistor resistance is good, then you may need to replace the electronic control board.
Common repair parts for JennAir bottom-mount refrigerators
- Condenser fan. The condenser fan is in the machine compartment of the refrigerator next to the compressor. It moves air across the condenser coils to help cool the hot refrigerant coming out of the compressor. The refrigerant is cooled before it moves through the expansion device and into the evaporator.
- Defrost bi-metal thermostat. The defrost bi-metal thermostat is a safety device attached to the evaporator coil. The defrost bi-metal thermostat shuts off the refrigerator defrost heater if the heater gets hot enough to damage the evaporator.
- Electronic control board. The refrigerator electronic control board controls the major electro-mechanical components in the refrigerator. When the electronic control board senses the compressor needs to run to cool the refrigerator, it sends voltage to the compressor and fans. It then receives input from temperature sensors to monitor the temperatures inside the refrigerator and freezer sections. With this information, the electronic control board controls the defrost cycle.
- Evaporator fan motor. The evaporator fan motor blows air across the evaporator coils and through the refrigerator cabinet for cooling. Replace the evaporator fan motor if it won't run when activated.