Chrysler Repair: 2004 300m climate control a/c, diagnostic capability, button mode

Question
The climate control in my 2004 300M exhibits problems on hot days when it has been sitting in the sun.  The temp display is blank but the snowflake displays.  Sometimes the unit blows very hot air on the floor and other times it blows cool (not cold) through the dash.  After the car is driven about 15 miles, it corrects itself and the climate control displays the temp and does what it can do so well.  I do not have any problems in the winter...just the hot summer days.  The dealership has thrown parts at this and yet has to repair.  I am tired of the expense but the heat that this system can blow is unbearable!  Any ideas?

Answer
Hi Pat,
There may be some electronic component in the control unit that is beginning to break down when it get overheated, but until it blows it would be hard to find.
There is some self-diagnostic capability that you can take advantage of.  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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