Chrysler Repair: 1994 LHS A/C problem, troutman pa, heater coils

Question
I have a 1994 Chrysler LHS that started giving problems last summer with the air conditioning.  When turned on, it would blow hot air on all settings.  I finally went and got a manual for the car today and as the manual and you suggested with another a/c issue posted here, the trouble code check has come up with a number 23, ATC blend door feedback control.  With that limited information, can you provide me with information about how to correct the problem.

Thanks!

David Troutman, PA

Answer
Hi David,
The blend air door is the device that decides how much air to send across the evaporator (cooling) coils and how much to send across the heater coils in order to get the desired air temp. The door is located on the left end of the unit and it is operated by an electrical actuator on the bottom of the unit at that end. The first thing to check is whether the door is free to move or binding and to verify that the actuator is operational so as to be able to operate the door lever arm. To get to the actuator you may need to remove an air duct in front of it at that left hand end. The actuator is a rectangular flat box with an electrical plug. It has a couple of "ears" that each has a screw on the underside which if you remove will allow the actuator to be dropped from the bottom of the unit. You will then see that there is a lever projecting downward which fits into the actuator. That is the blend door lever arm which you then can manually check for freedom of movement. With the actuator removed but still electrically connected try the code readout procedure again. If the code is no longer present then probably the problem was due to binding up of the door mechanism. Otherwise electrical testing of the wires to the actuator and the control unit proper will be necessary. I may be able to tell you which wires to check out, but I will need to compare the wiring of the unit you have with the '92 diagrams which are the latest I have to see if I have an accurate diagram for your car. So let me know what progress you get with checking for binding up.
Roland