How to Test an Appliance Thermistor with a Multimeter

What Is a Thermistor?

A thermistor is a temperature-sensitive resistor used in appliances to measure temperature. As temperature increases, a negative temperature coefficient (NTC) thermistor decreases in resistance. Appliance control boards use this reading to regulate heating and cooling.

A faulty thermistor causes false temperature readings, leading to error codes like E1 (Whirlpool fridge), 5E (Samsung fridge), E3 (Maytag dryer), and many others.

Tools Required

Step 1: Unplug the Appliance

Always disconnect power before working inside any appliance.

Step 2: Locate the Thermistor

Consult your service manual for the thermistor location. In refrigerators, it's typically clipped to the evaporator coils or in the fresh food compartment. In dryers, it's in the exhaust duct or near the drum.

Step 3: Disconnect the Thermistor

Disconnect the wiring harness connector from the thermistor.

Step 4: Set Your Multimeter

Set the multimeter to resistance (Ohms, Ω) mode.

Step 5: Measure Resistance

Touch the multimeter probes to the two thermistor terminals. Note the reading.

Step 6: Compare to Spec

Step 7: Replace if Faulty

Thermistors are inexpensive parts (typically $5–$25). Replace with an OEM part for your specific model.