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Chrysler Repair/No Heat: '02 Concorde ATC control


QUESTION: My question is I am trying to figure out what's wrong with my 02 Concorde 3.5 engine. I have took it to a Midas shop and a radiator shop and both could not tell me what's wrong with it. I get no heat, but some how both shops return the car to me with the heat working. They both said everything looks good with the thermostat and the heater core and hoses. I just want to know why my car's heat won't work and where or what to look for to try and fix this problem.

ANSWER: Hi Jose,
I can't explain why the heat is working when they return the car to you, but then you don't get heat the next time you try. Which type of control panel do you have? Does is have illuminated temperature settings on a digital readout or is it the non-readout type?
Is there no difference at all when you request heat instead of no heat? Or is it just less heat than you would expect? Is the blower motor working and does it give you several speed choices? Please let me know the answer to these questions.

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QUESTION: Midas suggested to flush the system. The other shop said he thinks it is a temp door actuator but could not be sure because the heat was working. I have a digital readout on the temp gauge. The problem was when I have it set to HI it only blows cool air no heat. I'm not sure if the shops just played with the temp gauge that's causing the system to put out heat. I was just looking for more info because it is getting time consuming to drop my vehicle off. thanks.

ANSWER: Hi Jose,
You can try a self-calibration of the unit by running the engine, then turn on the ATC control unit, then run if with the setting a full cold for 2 minutes, then run it at full hot for 5 minutes. That should calibrate the blend air door if it is out of adjustment.
Then the other thing you can do is ask the ATC control for any fault codes it sees in the operation of the unit. Do that by starting the engine, and set the temp for 75 F. Then press these three buttons AT THE SAME TIME (floor, mix, defrost...those are lower 4th button, upper 5th button, upper 6th button), then release the buttons after the display begins to blink. After a while the blinking will stop and either a two digit number will be displayed or the readout will return to normal. Tell me if you get any two digit numbers and we'll go from there. If by chance you do get a two digit number, then press the upper 4th button to see is another two digit number appears (e.g. a second fault code number).
Please read the PS below and respond to it.
Thanks for doing that,

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QUESTION: Ok I got a car repair book and did the code test. It came back with a number 36 ATC CONTROL COMMUNICATION FAILURE. not sure what to do next or what that part is, can you please explain thanks.

Hi Jose,
The procedure for checking out the code 36 is to use a volt-ohm meter to check the voltage supply to the ATC control unit itself, mounted in dash (the digital control for the HVAC system) and then to check the continuity of 5 wires between the unit and the body control module located also under the dash on the rear side of the fuse box at the left hand end of the dash (access to those plugs is from under the dash). If nothing wrong is found after doing those checks then the final step is to replace the ATC control unit itself. Let me know if you have a volt-ohm meter and would like to know the specific tests to do with the meter.

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Roland Finston


Get a Free Fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

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