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Remove power from the refrigerator before testing the thermistor. I just went through a similar problem. Are you comfortable working with a VOM meter? If to, it is easy to check the thermistor. To test the Dometic thermistor, disconnect it from the circuit board and place the other end (sensor end) into a glass of ice water. After a few minutes you should be able to get a resistance reading of 7,000 to 10,000 ohms between the two terminals of the connector. If the resistance isn't close to those numbers, it is bad.
To do this one must remove the thermistor from the slider it is mounted on. Do this carefully. Thermistors are very delicate. Remove the cover from the power control board. Unplug the thermistor connector from the board. Follow the above mentioned test steps.
There are some other simple things one can check:
1. Is the symptom the same when powered via propane or electric?
2. Is the thermistor on the right most fin.
3. Is the bottom of the thermistor slider about 1/2 way up the fin?
4. Is the thermistor securely in the slot made for it, completely enclosed by the slider?
5. When the bottom of the slider is about 1/2 way up the fin, is the thermistor part of the slider still on the fin?
6. Moving the slider down will raise the temperature. Moving the slider up will lower the temperature.
Please post the results here.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
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