Think the whole unit requires replacement
After following this post and doing a little research on the thermistor, it can be easily obtained if that is the culprit, for about $3.70 in parts, you do the labor. I have the same problem as others and think the $3.70 can fix mine but it is also in celcius. Unfortunately that is greek to me and don't wish to carry a calculator with me to figure out it's either to cold or hot outside.
Looking at radioshack.com they also had some thermistors that might work that all ran $.59 if you care to look.
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