Chrysler Repair: 1999 Concorde Heat Blows Cool Air, concorde lxi, panel button

Question
I have a 1999 Concorde LXI.  When I have the heat on (climate control) and I pull up to a stop light or just let the car idle (warm up), the air that comes out is cool.  However when I press the gas, the warm air picks up again.  Why do you think cool air blows out when the car is stopped (idle) but once in motion the warm air kicks back in???  Any ideas prior to taking it in to be evaluated.  Thanks


Answer
Hi Pete,
It may be that you have some air trapped in the heater core, which becomes more evident at the lower water pump circulation rate at idle speed. There is a special funnel and filling procedure needed to refill the drained system so if that was done just before the problem appeared that may be your answer.  Or the heater core itself could be partially clogged and act like an air bubble in that respect at idle speed. It might also be a problem with the ATC control or actuators. The system can do self-tests:
Have the engine idling. Set the temp to 75>sno F so that the two digit trouble codes won't be confused with temp readings. Then simultaneously press the  floor, mix and defrost buttons (the three at the right end) and hold while the readout begins to blink, then release. The unit will continue to blink and finally if there are any codes it will display them. If there are no codes the C or F will ultimately return to the display. Otherwise watch for two digit code to appear, then press the panel button to scroll thru any additional codes in the memory. Only press the panel button or the additional codes will be lost and you will need to repeat the readout. Write back with any codes that you find and we can go from there.
Roland
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