I don't think it's the blend door. I can change it from "60" to "90" (digital climate control) and it'll blow hot air. When the compressor is running but not blowing cold air, I can just push the a/c button and it'll kick the compressor off with the blower motor still running. Then push the a/c button again to turn on (or sometimes 15 times) and then it'll blow cold. All without adjusting the temperature.