On 11 August, I took our 2001 Aero 9-5 with manual tranny out to run errands and posted the following.
"Driving down the highway, it is throwing heat. Outside temp reads 78 (and climbing because I am losing altitude as I head towards Denver from
2000 feet above it) and it is not like the A/C is not working, it is thinking I need heat!"
I got some advice from DervMan through posts on this group and I can report the following which I did today:
1) Pressing Auto and Off simultaneously will reboot the system and check for errors, reporting error number (0, 1, 2...) and error code. The first time I did this I got one error, 12. The Mitchell on demand system (CD-ROM shop manual) listed this as a door stepper motor open or short to ground. This makes some sense as maybe the door which regulates whether you get heat or A/C air was not funtioning and set on the heat side.
I restarted the system twice after that and received 0 errors and it works fine now. I am thinking there was an intermittent loose connection or short, which may or may not reappear.
I can look up error codes if you have one and don't have a reference.
I wonder how hard it is to get to this door...
Charles