Good write up, but two things:
Originally Posted by
xintersecty
If you have the AC pump turned off and the temperature selectors turn(ed) to full cool and the hot air comes out of the system, the the coolant circulation valve needs maintenance. You can buy a rebuild kit for the unit off of amazon.
If one or both sides are stuck OR if there is no 12 volt feed to the center pin (I had that once), you will get hot air if the engine is warmed up, having the A/C pump on or off won't matter, because the coolant temperature will be at least 188F - and the air flows thru the heater core(s) after being cooled by the evaporator.
Of course looking in the manual you can't find anything called duo-valves. I eventually found what is the proper name: Coolant circulation valve.
Chrysler calls it that, Mercedes calls it a duovalve because there are two valves in the assembly.