Besides, I'm not saying that my answer is the correct one. Just one of the many possibilities. As anyone knows, you can't diagnose a problem over a computer without even looking at the car. I just thought I would give a quick opinion. But if some people want to be sticklers about it, let me ask this; what is the year make of the car, how low is below normal, how much heat is comming out of the vents with the heat on? When you do a cold start with the A/C off and the defrost off, are the electric cooling fans running? I originally thought this was a friendly site, but maybe I was wrong