As I read the AFM for my airplane, my impression is that the auto temperature control should allow you to set a temperature using the control knob, and the system should maintain that temperature.
That isn't how my system works. In my system, you have to set it to full cold on the ground (unless it is very cold, in which case maybe you turn it 30 degrees from full cold), and then turn the knob about 90 degrees at altitude (by "degrees" I mean degrees of knob rotation, not temperature). Before you start down, you need to go to full cold again, or it will get really hot about the time you get down to 5,000 feet or so.
I've had my cabin temperature sensor checked, and it's working find and has been cleaned up.
Is that just how it's supposed to work? I sort of thought "they're all that way" but then again, I was always told to just use the manual override, which I find to be unnecessary, at least in my airplane.