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Phantom operation HVAC controls Jeep Patriot

Discussion in 'Compacts: Renegade, Patriot, Compass, Caliber' started by AllanC, Nov 10, 2017.

  1. AllanC

    AllanC Well-Known Member

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    I encountered a strange phenomenon with my 2016 Jeep Patriot earlier this evening. Vehicle has about 36,700 miles on the odometer. It has manual control heater and air conditioning / HVAC system. I was installing a seat cover on the driver side seat when I started to hear a climate control motor actuator power up. To me it sounded like the recirculation actuator either opening or closing. Ten to 15 minutes the same actuator powered up. And 10 - 20 minutes later the same actuator powered up. I was working on the seat cover for about 1 hour total time and the actuator powered up 3 times.

    The key was NOT in the ignition. The left front and left rear doors were open. The interior dome lamp and other lamps were switched OFF with the control on the turn signal stalk. I was moving the driver seat forward and backward while installing the seat cover. I wonder if moving the seat was generating some vibration that somehow affected the actuator position feedback circuit between the actuator and the HVAC electronic controls?

    You would think that with the ignition in the OFF position and key removed, the actuators should not suddenly power up. So there is some phantom operation occurring with the HVAC electronic controls.

    The HVAC controls are probably engineered for similar operation in all late model Chrysler vehicles. Has anyone encountered this rather strange behavior? Any TSB about HVAC control behavior?

    The only concern this causes me is that if this goes on continually and the vehicle sits for an extended period of time, the battery could be depleted prematurely. I will have to see if I can recreate the situation.
     
    #1 AllanC, Nov 10, 2017
    Last edited: Nov 10, 2017
  2. OfficialMopar

    OfficialMopar Official Mopar Reps
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    Hi AllanC,

    If you end up deciding to visit your local dealership for further diagnosis I'd be happy to offer assistance if needed. Just send us a PM with your VIN and let me know!

    Andrea
    Mopar Social Care Specialist
     
    RonGD, Hankster and ImperialCrown like this.
  3. ImperialCrown

    Level III Supporter

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    If the vehicle doors were open, then certain modules would have been awake. I don't know why the actuators would have been cycling. If a door was closed and re-opened, it may have cycled the HVAC actuator again?
    There are no TSBs or HVAC operation descriptions that mention this phenomenon.
    If the doors are closed and locked with a window rolled down, try listening for the same noise? The recirculation door may stay open to vent any stagnant air or odors from forming in the interior? OTOH, they may want to close the recirc door to keep mice out? There is a HVAC intake air screen to keep mice out, but it didn't always stop them.
     
  4. AllanC

    AllanC Well-Known Member

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    I was NOT expecting that someone associated with FCA would be monitoring this forum and offering to provide assistance. That is certainly encouraging!

    This vehicle has a CPO designation (certified pre owned) and the bumper to bumper warranty extension expires on Jan 3, 2018. But intermittent problems like this are very difficult to isolate and pinpoint a specific cause. I am going to investigate on my own and see if I can recreate the phantom operation inputs before getting a dealership service department involved.
     
  5. AllanC

    AllanC Well-Known Member

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    I would tend to agree that with a door open certain modules are still awake, processing and awaiting any commands to perform a function. I do know that if the ignition switch is in the RUN position and you turn the fan speed control knob to OFF position, the HVAC recirculation actuator powers up and closes this door. My 2000 Grand Voyager and 2008 Dodge Avenger behaved in the same manner.

    If the fan speed control is in any position other than OFF and you turn the ignition to the OFF position, after a few seconds of thought, the recirculation door actuator powers up and closes. I believe this is intended operation.If I remember correctly the vacuum controlled Chrysler HVAC systems would behave in the same fashion. Turn the fan OFF and the recirculation door would close.

    In this particular instance the fan speed control was in position 1 or the lowest fan speed setting possible. Maybe that might have a bearing on the phenomenon. Another input to check.

    One can always hope that someone else has encountered the same situation. Oh well, guess I get to be a pioneer and see if I can discover something. Even though I claim senior citizen status my hearing is still good and I know what I heard was authentic. :)

    I would just love to have an audience with the engineers that designed and programmed the smart logic for the HVAC control system. In the attempt to create a better system inadvertent logic sequences that result can cause rather strange behavior. This is really no different that writing and debugging a complex accounting system with payables and receivables. The situation that no designer ever thought could or would happen HAPPENS, and output results get squirrelly!

    As always I C thanks for your input. If I discover anything I will post again.
     
  6. Doug D

    Doug D Virginia Gentleman

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    I can't say for sure but I believe I've heard the HVAC doors cycle or some sort of movement (perhaps calibrating) on my '06 Ram and '10 Journey shortly after shutting the HVAC controls off. I don't recall if this happened with the ignition on or off.
     
  7. AllanC

    AllanC Well-Known Member

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    I performed some investigative tests and I find that the "phantom operation" of the HVAC recirculation door is programmed in the logic that operates the HVAC control system. I sat in the vehicle and turned ignition to the RUN position. I had the system set to floor heat with blower on low speed. I turned ignition to OFF and removed the key. I then opened the driver door and left it open.

    I heard the recirculation actuator power up and move its door. I started a timer and then waited. After 4 minutes the recirculation actuator powered up and moved its door. After 10 seconds it powered up again. While this was happening it sounded like the temperature door actuator powered up twice and moved its door. I repeated the sequence and after 4 minutes the same sounds appeared.

    So it looks like the "phantom operation" that I suspected is in fact logic programmed into the HVAC control module. I am not sure why Chrysler engineers think this HVAC door movement is necessary after the driver has exited the vehicle but as others have suggested maybe it is to vent odors, prevent rodent intrusion, cure pimples, etc !

    I also discovered that without the door opening and closing gymnastics and with vehicle sitting untouched for several hours, if one presses the TIME button on the radio the time is illuminated on the radio screen. Also the recirculation actuator powers up. After 4 minutes it again powers up.

    So the unexpected, phantom operation is a direct of result of Chrysler engineers knowing better than us. Problem solved!
     
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  8. ImperialCrown

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    I have also noticed on some newer vehicles that the odometer display lights up if you try to open the drivers door (even if the door is locked).
    This is useful for dealers and rental companies that need to log the current mileage and don't have the keys for the vehicle handy.
     
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  9. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Allan, this is normal for the HVAC controls to "home" themselves when a door is opened within hours of the car being run. I don't agree with the logic, but it is normal.
    Reason I know is, my wife's 2012 Chrysler 200 had a defective recirc motor that was clacking loudly whenever we changed ANY climate control setting, including turning the fan on or off. It also made this noise over 20 minutes after driving, with key out and car parked, if a door was opened.

    We replaced the motor and it was quiet for awhile, but now the recirc or other door creaks and groans badly, whenever any climate control is set, and whenever a door is opened within an hour or so of being run. Not sure if the door is sticking, or if there is a calibration we were supposed to perform after motor replacement, but the car does 'home' the settings upon any disturbance. So do not 'poke the bear'. :)
     
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