Doesn’t matter if heat is on or not. The if the air direction knob were a clock, 12 o’clock would be 100% floor. 7 o’clock would be in your face. 5 o’clock would be 100% windshield. Any setting right of 11 o’clock activates the ac. It’s like it’s jumped a tooth so to speak. Only other problem going on is the thermostat sticks open and has the p0126 code. I erased it and it comes back in a day or two.