HVAC on the fritz

Discussion in 'Generation 4 - Maintenance & Troubleshooting' started by longliveSHO, Jun 12, 2019.

  1. longliveSHO

    longliveSHO New Member

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    Hi guys, got a weird one for ya today...

    I recently replaced my blower speed control module and forgot to do whatever dance afterward to prevent future HVAC problems. Currently reaping the consequences :biggrin:

    Anyway: I seem to have two separate issues. 2011 SHO, non-pp, with MyFordTouch.

    1) I can no longer select where the air goes, it stays on the face vents permanently. Scouring the forums here it looks like the actuator for that blend door has failed. Normally, I would pull the trigger and order the part, but i've noticed that the recirculate door magically stopped working at the same time. I still have independent temperature control, on both the driver and passenger side. Might something larger be amiss here or do these just fail this often?

    2) My air conditioning will not shut off! Not a normal failure mode on most vehicles. Even if the button is not lit up, I get freezing cold air out of the vents. I can turn the temperature up and add heat, but that just seems like a waste.

    I have tried resetting the HVAC module (pull fuse #15 under the dash, turn the car on for 30+ seconds, off, replace fuse, turn car back on) and until I mess with any settings the A/C will be off. As soon as I mess with the temperature or try (in vain) to direct the air somewhere else the A/C turns on and the air is cold.

    I'm at a loss! Anyone seen something like this before? The issue with the blend doors happened first, which prompted me to reset the HVAC module. Since the first reset the A/C issue has been present. I'm starting to lean toward the failure of the HVAC module given the multiple failures at once.

    Thanks!
     
  2. Johnbigdog

    Johnbigdog SHO Member

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    Have you tried a battery disconect?
     
  3. longliveSHO

    longliveSHO New Member

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    Hadn't yet. Just did, now have a fresh set of results:

    Both of those blend door actuators (vent selection and recirculation) are definitely shot. You can hear them hunting back and forth for a position just like all the videos online.

    I can now turn the A/C on and off, but only when the selector is set to face vents only. As soon as any other selection is made the A/C turns on and stays on regardless of the A/C button. Once the face vents are selected again, the A/C does whatever the button says. Air always comes out of the face vents in any case.

    I got ahold of a workshop manual. I think it's time I bought a code reader, there is a symptom in the chart for "The air conditioning is always on - A/C mode always commanded ON" with a bunch of associated codes. Any recommendations for a reasonably affordable standalone code reader from the community? I could also be tempted to go the adapter/FORScan route but it'd be nice to have a more universal solution. I have a Jeep in the fleet as well. Needs to be able to read those B, C, and U codes.

    One of the fixes is to replace the PCM, since apparently it doubles as the body control module? Another lists the navigation screen as a culprit. I really hope neither of those are the case.

    That said, I have a suspicion that the PCM (connections at least) may be worth a look - The original owner of this car apparently parked it outside for the entire time they owned it. The sunroof drains were absolutely clogged with tree sap and seeds when I got it and I have a feeling the cowl drains are no different. The PCM sits in the cowl area, and lately when I leave the car wash I can hear water sloshing around in there. Hopefully the PCM hasn't been swimming for the last few weeks/months.

    Will report back with any findings.
     
    Hebes10 likes this.

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