First off I am new here and I joined to see if I could get some kind of idea on the problem I have with my heat. I have the dual control digital unit and the only way the heat works is if it is on 90 degrees. If you even turn it down to 89 degrees the air goes cold which should not be a big difference between being on 90 degrees to 89 degrees . I have noticed that my ambient temperature on the mirror is way off so I was wondering if the ambient temperature sensor was bad or do I have a bad climate control unit? Any help would be appreciated.