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A/C vent selection changes on its own?

Tiny
TXREDNECK911
  • MEMBER
  • 2015 SUBARU OUTBACK
  • 2.5L
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 140,000 MILES
Last year my wife’s A/C stopped blowing out of the vent. I could hear clicking under the dash. After researching I replaced the blend door actuator motor. In the end, I also replaced the control panel. All has been well.

About a month ago, it started happening again but differently. Air will come out of the front vent for a few minutes and then changes to the floor on its own. Cycling through the vent directions, air will come out of the vent again, but only for a few minutes at a time. I can also hear the clicking under the dash like before.

The battery is about a year old and passed testing. Same with the alternator. Battery terminals are clean and so are the cables.

I am skeptical that the blend door actuator is bad again. And if it is, is something electrical killing the motor?

Can you help me diagnose it? Is there a way to test the BCM?
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Wednesday, June 26th, 2024 AT 5:28 PM

14 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

The BCM isn't causing this to happen. Interestingly, the blend air door actuator is responsible for the air temperature entering the vehicle. In this case, air flow changing direction, it sounds like the mode door actuator is failing.

I attached a picture of the mode door actuator. What we need to do is determine if that is where the clicking is coming from. Usually, the small plastic gear in the actuators strip and you hear the noise, and the component fails to operate properly.

Let me know.

Joe

See pic below.
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Wednesday, June 26th, 2024 AT 9:25 PM
Tiny
TXREDNECK911
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Thank you for the reply. We may have a mix-up in terms. The mode door actuator was replaced. I have seen the part being referred to as blend door actuator so my apologies for any confusion.

Is it possible the mode door actuator is bad, even though I replaced it less than a year ago?
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Thursday, June 27th, 2024 AT 3:36 AM
Tiny
TXREDNECK911
  • MEMBER
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I am attaching a video. You can see the mode motor moving back and forth.
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Thursday, June 27th, 2024 AT 6:11 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Unless you are changing the airflow direction very quickly, it shouldn't be doing that. And yes, the actuator may have simply failed again.

No problem with the actuator terms. In general, there are too many terms to remember. LOL My favorite is trying to keep up with all the different acronyms. LOL

Let me know if the actuator was doing that without you requesting change.

Joe
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Thursday, June 27th, 2024 AT 8:32 PM
Tiny
TXREDNECK911
  • MEMBER
  • 9 POSTS
It does that without any input change from the panel. As we drive, we can hear the motor moving back and forth under the dash.

The motor is supposed to be covered by a warranty. I’m wondering now, if I replace the motor again and it fails, what is happening to shut off the motor.
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Saturday, June 29th, 2024 AT 8:52 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I would replace it. Unless there is excessive strain on the motor, it is the part itself that is failing. They are making things cheaper and cheaper.

Actually, remove it, get one under warranty, plug it into the wiring, and see if it does the same thing. If it does, then we need to start tracing the wiring to the controller or scanning to see if there are any faults related to the HVAC system. If it doesn't, it's the part and the new one will likely fail as well.

Let me know,

Joe
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Saturday, June 29th, 2024 AT 7:39 PM
Tiny
TXREDNECK911
  • MEMBER
  • 9 POSTS
I want edto give you an update. I submitted for a warranty replacement. It’s a really long story and doesn’t make any sense, but I found a new motor while looking for a box. I plugged it in and cycled the modes and seems to be good, but I’m cautious. I did all this on Sunday.

The wife drove the car to work today and everything worked great. I will give it until the weekend and I’ll let you know how it goes.
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Tuesday, July 2nd, 2024 AT 8:28 PM
Tiny
JACOBANDNICKOLAS
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Hi,

That's good news. Chances are it will be fine. Let me know if anything changes. Hopefully, the problem is resolved. LOL

Take care of yourself and Happy 4th of July!

Joe
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Wednesday, July 3rd, 2024 AT 7:38 PM
Tiny
TXREDNECK911
  • MEMBER
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Hi friend. I’d like to give you an update.

For the most part, everything is working as expected. Forward selection results in forward air, floor results in floor, etc.

But my wife said the amount of air was not as much as it used to be. It was then I noticed that there is a small amount of air that is coming from the floor vent, even when the front vent is selected.

The selection motor was a pain to get back in place to get all three arms in the appropriate channels. Did I miss something?
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Thursday, August 29th, 2024 AT 2:21 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I can only think that some grease may have been needed on the rail plate. It could be hanging up a bit if you didn't do this. Although I do this, it isn't always required.

I attached a pic below and highlighted the areas I'm referring to.

Let me know.

Joe

See pic below.
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Thursday, August 29th, 2024 AT 7:15 PM
Tiny
TXREDNECK911
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I added a dab or two or grease when it was reinstalled. It was such a pain to get in place are there any reference marks I could use. Any recommendations which position the doors should be in when I install the wheel?
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Thursday, August 29th, 2024 AT 8:25 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

The positioning shouldn't matter. I attached the installation directions below for you to review. There is nothing indicated for alignment or relearn. However, they do stress the grease. Actually, it indicates adding the grease and operating the actuator several times prior to installation to evenly spread the grease.

Take a look.

Joe

See pic below.
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Friday, August 30th, 2024 AT 8:12 PM
Tiny
TXREDNECK911
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I have the same image but there are 3 doors that have to be in a specified position to fit in the channels. That is a challenge with one hand.
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Friday, August 30th, 2024 AT 9:19 PM
Tiny
JACOBANDNICKOLAS
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Hi,

It certainly is a pain. LOL I don't want to say it, but I think you need to remove it and re-lubricate it.

Let me know.

Joe
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Saturday, August 31st, 2024 AT 6:23 PM

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