I have Frigidaire side by side refrigerator with defrost problem. I assume, I figured out defrost thermostat problem by checking its connectivity. I did it by using multimeter and measuring the resistance above 40 degree and dipping the thermostat under ice water for 5 minutes. I found infinite resistance (open) during both times.
Then, I purchased the new thermostat and run both tests exactly. This time also I see infinite resistance (open) during both times. Now, I am confused why the defective one and the brand new one show the same testing ?
Ice water may not get the thermostat cold enough to test it.
The operating temperature should be marked on the side of the thermostat.