Applianceman and Richappy, I cannot thank you enough for your response. which was quick and right on the money. I ordered the thermistor (you were correct was under $7.00), went to Lowe's and found couple of connector (prefilled with slicon). Located the the supposedly faulty thermistor behind he eveporator (real pain as not much space between eveporator and back wall). This sensor was inside a metal sleeve, tied to the back of eveporator. I cut the existing thermistor wires and reconnected the new one with silicon prefilled connectors (Lowe's associated was sure the connector he gave me would insulate the copper wire and seal it from any moisture. Reinserted the new thermistor in the
metal sleeve just like to one I removed. I turned on the refrigerator and reset the temp at 37 deg. It has been 8 days now and the refrigerator is working great with no frost on eveporator. In past I would have seen teh evaporator partly frosted and temp warming up in 6-7 days. I thought, I will share theis with you an dany one else having similar problem. I can come back and post in one week ot assure this has worked.
Hey! Thanks again, awesome forum, people and advice.