I was wondering, before I go tearing things apart, is there a way to manually set all the flaps in these damn things to either hot or cold?

My car blows cold on top vents and seering hot on the lower...slowly setting to all cold then BACK to hot allows normal operation for a minute before it gives way again to outside air which is 5c or like 42F and freezing.

AC is disconnected don't need cold air any time soon.

 

Not easily, the flaps which control temperature and air position are motor controlled. You can control them with a 555 timer and some electronics to set position but a lot of work especially for someone with no electronic knowledge.

Here is a copy of the diagnostic information go through these and see if the issue is a sensor. If it's the ECU these are getting hard to find and there are many different CC ECU's and not all are interchangeable.