I have a 2014 Impala LTZ with 42,000+ miles. Last Friday the ac would not come on. Probably the first time I have tried to use it in a long time. The sunroof has not worked in a few months. I do not know if this has any bearing on it but we tried to open the sunroof when it may have been frozen shut. At least when the sun roof first didn't work we did have much ice on the car. Not too encouraging to have these problem on a car 2 years old.