Chrysler Repair: 95 Chrysler Concorde ATC head unit, digital data communication, chrysler concorde

Question
My Concorde will rarely let me use the heat or air conditioning.  Most of the time the heat is stuck on high from the defrost vents and the digital display and controls don't work.  I was able to do the diagnostic check on a day when it did work and came up with codes 31 and 36. 31 says ATC recirculation door stall failure which I'm not very concerned with unless you think I should be.  36 says ATC head communication failure.  I am pretty sure from what I've read that the ATC head unit is the problem and I'm willing to replace it unless you suggest otherwise.  My main question though is where is the ATC head unit and how would I go about removing it.  The book I'm referring to doesn't cover hor to remove the ATC head unit.

On a side note the radio seems to have similar problems.  Rarely does it light up and allow me to control it.  If it does happen to work it sometimes shuts off in the middle of use and will switch to a static station and play it at whatever volume I had it set to but cannot be shut off.  I don't know if there is any relation between the two problems but the heat/air is my main concern.  If you could solve my radio problem that would be great too.

Thanks


Answer
Hi Phillip,
The ATC head unit is the control panel itself. All you have to do is remove the ash receiver, gently pry off the lower center bezel to give you access to the sides of AC control panel where there are screws that hold it in. Remove the screws and pull the unit out and disconnect the two plugs at the rear.
You might want to verify the wiring of the digital data communication twisted wire pair: look for the white/black and violet/brown wires (pins 3 and 4) on the harness plug and check thay they are continuous to the data link blue 6-pin plug under the dash near the steering column. You could also open the unit and try reheating the pins on the plug socket (pins 3 and 4 of the 8-pin socket) where they join the internal circuit board and where there is a solder connection that might have fatigued. Use a soldering pencil for that task. The problem could just be a loose solder joint rather than something inherently wrong with the control head.
If that doesn't work, then find a replacement at a wrecking yard.
The radio does not have a connection to this data system as far as I know so it is an independent problem.
Roland