Chrysler Repair: Chrystler LHS ATC heater temp problem, code 23, volt supply, feedback signal

Question
My friend is having a problem with her heater. It doesn't put out heat when it is Idling but it does when you are accelerating. I ran a heater diagnostic and received code 23. What is it and where is it and how can I get to it, is my question

Answer
Hi Alan,
The 23 code says that the feedback signal from the blend air door, which is the one that controls the temperature of the air, has for some reason failed. The ATC controls that door but to do it properly it has to get a feedback signal telling it about the present location of the door. You could do some circuit tracing to verify that the 5 volt supply for the feedback signal is working and that the connection from the blend air door motor that is supposed to carry the feedback signal is patent. To do that you need to remove the trim panel in front of the passenger side door under the dash to get to the body computer and then do some measure with a voltohmmeter. An alternative is to assume that the voltage supply and feedback signal path are o.k. and thus that the feedback signal generator device in the blend door motor, which is located on the underside of the HVAC box under the dash, has failed. You would then either go to a pull-it-yourself wrecking yard and get a blend air door motor or check what the price for a new one is with the dealer.
You need to simply remove the under dash lower panels so that you can get access to the blend air motor which is located just above the center hump, and then  go to the motor and remove it. It is probably a bit of a gymnastic manoeuver but is tractable. I can send you the pages from my '94 manual that show the circuitry and the blend air door and how to access it.
So that is my assessment of the situation. Let me know a postal mailing address and I will xerox and postal mail you the necessary pages. If I am "maxed out" use the "rate the expert" tab where you will find a comments area to enter a text message.
Roland