The newer GE and Hotpoint refrigerators use a thermistor to sense temperature. The motherboard on the back of the refrigerator sends an electrical pulse to the sensor to measure its change in resistance and thus sense the change in temperature of the refrigerated space. So, checking the thermistor comes down to simply measuring its resistance at a known temperature. This topic in the Samurai Appliance Repair Forum gives you the temperature-resistance information you need to test the thermistor.
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