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Me Fix 04-23-2011 01:54 PM

Dual Zone Heater Control Doors
My used 2004 Overland came with some issues. The dimming mirror and now the heater control doors. I have noticed that many Grand Cherokee owners of 2002 to 2004 models experience broken door problems. I think the door hinges usually break after numerous calibration cycles which drive the doors to their limits while stalling the drive motors causing high current draws which tell the controller that the doors are at end of travel. This stalling at limit usually breaks the door hinges and can set error codes which can be read on the digital readout of the control head. Yes, I do have error codes 52 and 56 which suggest over travel of the zone doors. It seems that every time I turn off the keys, the heater controller does a calibration cycle within a couple of minutes. Calibration every key cycle seems to be excessive. I read where this should happen every 20 or so cycles. Maybe because I have error codes, the calibration cycle happens every time I shut off the key. It usually take about two minutes to start the cycle and when it starts it sounds rather like rubber rubbing the plastic housing very hard. I think this everytime cycle will eventually break the door hinges making me fix them. has anyone else delt with this issue? Again I have read about after market doors and even fixes that can be done without taking the whole dash out. That fix usually turns the dual zone control into a single control unit and if that is true, it might cause a calibration cycle every key cycle again. not sure I want that.

Frango100 04-23-2011 02:24 PM

Re: Dual Zone Heater Control Doors
I also hear some doors moving a few minutes after switching off the car and it always have done so. I don't think that it is calibrating the system, but just shutting the control doors. At the end of the travel its indeed making some rubbing noise. Sofar the system didn't give me any problems, but many others already had the "joy" of doing this repair or paying big bucks for someone to do it. Seems to be quite a bad design from Jeep.

Me Fix 04-25-2011 09:50 AM

Re: Dual Zone Heater Control Doors
Frank, Do you have any error codes stored in your controller?

Frango100 04-25-2011 12:17 PM

Re: Dual Zone Heater Control Doors
Will have to look tonight, but the last time i had looked (some year ago or so) there where no faults stored.

Frango100 04-25-2011 12:18 PM

Re: Dual Zone Heater Control Doors
Will have to look tonight, but the last time i had looked (some year ago or so), there where no faults stored.

Frango100 04-26-2011 10:11 AM

Re: Dual Zone Heater Control Doors
Checked for fault codes, but only showing 0, so all ok.

Me Fix 04-26-2011 07:16 PM

Re: Dual Zone Heater Control Doors
No faults in your system. The reason I was wondering is because you did say you hear some "activity" after you turn off the key. You suggested that you didn't think the "activity" was part of a calibration cycle, but rather just the doors closing. Maybe that is what my system is doing too, but i do have error codes stored and so I still wonder if because of the stored error codes, my system does do a calibration every time I turn off the key. May a Jeep engineer would be able to answer that one. I just think that if it is doing a cal cycle every key cycle, sooner or later something is gonna break. If I really knew what might happen, I'd rather fix it at my convenience now instead of having the whole thing fail during a trip or at any other bad time. Thanks for taking a look at your system. Gathering data never hurts.

Take Care

Frango100 04-26-2011 09:13 PM

Re: Dual Zone Heater Control Doors
The codes 52 and 56 you have are respective for the recirculation door travel too large and right temp door travel too large. Did you try to reset them first, they could be historical faults. Just press the A/C switch for 3 sec. or more when you are in the fault mode and it will errase the historical faults. Existing faults can not be errased this way. You could disconnect the battery for some minutes as well to clear all faults and try again.
Did you try to do the manual calibration? If not, heres the procedure:
Calibrating AZC door actuators

Calibrate the door actuators after making any repairs to the AZC system. To calibrate the door actuators proceed as follows:
1. Turn the ignition on.
2. Set the AZC to automatic.
3. Turn the ignition off.
4. Remove the IOD fuse from the Power Distribution Center. Wait several seconds, and then install the IOD fuse.
5. Turn the ignition on. Do not touch any of the AZC controls for at least one minute to allow the calibration function to run to completion.

Every 20 key cycles the AZC head initiates a re-calibration routine which identifies pulse counts required to achieve full door travel. Also during this routine all modes and functions are validated as functional. When the self calibration routine is complete, the control head resets itself to its last settings. The air conditioning compressor will engage in certain modes to cool and remove moisture from air entering the passenger compartment. The AZC control, when it is not set in the auto mode, always defaults to A/C enabled. The LED illuminates when the control requests A/C. The customer must toggle A/C off by depressing the button every time he turns to manual mode or the A/C is enabled. Additionally, when the vehicle is off for a "calibratable" amount of time, automatic A/C is again enabled and the customer must again force it off by depressing the button.

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