We're starting to get cool mornings while the afternoons are pretty hot, +90F/+32C. So I'll set the AC temperature to 78F/25C and life is good on the way home. But the next morning when it is cool 68F/20C, I got the impression I was getting cabin heat out the vent as I had not changed the temperature setting.
Did I by accident run the cabin heater?
For now, I see that AC has a light indicating it is working. I've not seen a heater working light. Did I miss the memo?