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Chrysler Repair/'08 300c heater conrols: diagnostic codes


I have a problem with heat coming from one vent and cold coming from the other. I have read where people say to calibrate the vent doors? I have tried what they say to do....but doesn't seem to be correct with my year? Is there a way to do this at home or is this a dealer only job?

Hi David,
As best I can tell if your unit is the automatic temperature control type which has separate controls for the temp on the passenger and the driver side then the calibration of the unit has to be initiated with a diagnostic readout box. The manual control unit however can be calibrated without the box.
There is a blend air door located on the passenger end of the HVAC box under the dash. That is probably what is out of calibration or malfunctioning. The control unit has self-diagnostic capability but again the ATC type needs the DRB box to get the fault codes, while the MTC can divulge its codes without the DRB. The DRB has to be able to access the HVAC control module via the plug that is under the dash by the steering column.
So if you have the ATC it appears that other than removing and replacing/checking the function of the blend door you need the intervention of someone with an appropriate DRB to get the fault codes/calibrate your unit. Once you have the fault codes let me know as there is a lot of detail on correcting each one of those.
The ATC codes are 4-digit and preceded by a B or a U. The MTC codes are 2-digit numbers.
If you have the MTC unit let me know.

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Roland Finston


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