Chrysler Repair: 04 Concorde: ATC doesnt work, temp out of control, atc system, diagnostic capability

Question
There is no correlation between the temperature setting on the auto temp control and the cold or heat coming out of the vents. Set the temp at 79 and the air coming out of the vent is in the low forty degree range.  That is the range for max a/c.  Moving the temp up or down changes the temp of air sent to the vents either up to max heat or it remains at near max a/c.  If you get lucky it will end up somewhere in the middle and you will be comfortable for a short period of time.  Then it starts all over again.  Has been doing this for years, now driving me crazy. Dealer no help. Can you help??  Thanks

Answer
Hi Dewey.
There is a self-diagnostic capability built-in to the ATC system. To use it, start the engine and set the temp control to 75 degrees. The car should not be in motion.  Then simultaneously press and hold three buttons: the floor (lower of the 2nd from the right), mix (upper of the 1st from the right) and defrost (upper of the right-most button) mode buttons.  The readout will start blinking. Then release the 3 buttons simultaneously. The readout will continue to blink. It will seek out fault codes stored in the body controller memory, and also try to calibrate the internal door/actuators which might cure the problem.  Then watch for a two-digit number which may show on the display after a while. Note it, then press the panel button (upper of the 2nd from the right) to see any other possible numbers and keep pressing that button until the display returns to show the temperature. Write back with the two-digit numbers you observed on the display and I can tell you what to do.
Roland
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