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HVAC Blower working hard, minimal airflow

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Hutch-3, Oct 30, 2024.

  1. Hutch-3

    Hutch-3 New Member

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    2014 Prius V (3rd Gen) 200,000+, AC blower: I can hear the blower speed change when I adjust the speed control. When it is cool, it blows a heavy airflow in the morning. However, after a while, later in the day while traveling, the outside temp is in the 80's. The AC sounds like something is restricting the airflow on high while cold air continues to come out. I selected different Blend door options, defrost, floor, and cabin; it sounds and feels like these are working correctly. But the airflow feels restricted.

    I attempted a troubleshooting code test by holding Refresh&Auto while turning the power on. The system blinked for a while, only showing "00" on the display.

    I noticed a 1' x 3/8" foam piece lying horizontal behind the three upper vents. I also recently changed the cabin air filter and double-checked that it was installed correctly.

    Wondering if the issue has something to do with a possible temperature component. You now know everything I know; if I told you more, I would lying! ;>)

    I value any input that can be provided.
    Respectfully,
     
  2. Air_Boss

    Air_Boss Senior Member

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    Does cold airflow increase when you turn the round automatic temperature controller to its minimum low?
     
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  3. Hutch-3

    Hutch-3 New Member

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    Air Boss,
    No, the airflow does not increase when I turn the knob down.
    If I remember correctly, when testing the system a couple of mornings ago, while the outside temp was still low and the airflow/fan was running correctly, the airflow did increase. However, when I turn the temperature control down during the afternoon heat of 82 degrees, the airflow does not increase.
     
  4. rjparker

    rjparker Tu Humilde Sirviente

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    The airflow will only increase with a lower setpoint IF the AC system is in Auto. The moment you adjust the airflow manually the system turns Auto off.
     
  5. rjparker

    rjparker Tu Humilde Sirviente

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    The foam piece does not sound right.

    A common issue is the air mix door C but there are others as well.

    Second illustration is the hatchback dash but the v airflows are the same.
    IMG_6576.jpeg IMG_6577.jpeg IMG_6578.jpeg
     
    #5 rjparker, Oct 31, 2024 at 11:57 PM
    Last edited: Nov 1, 2024 at 12:08 AM
  6. rjparker

    rjparker Tu Humilde Sirviente

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    No foam piece in center vents

    IMG_6582.jpeg IMG_6583.jpeg IMG_6584.jpeg
     
  7. Hutch-3

    Hutch-3 New Member

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    Air Boss,
    No, the airflow does not increase when I turn the knob down.
    If I remember correctly, when testing the system a couple of mornings ago, while the outside temp was still low and the airflow/fan was running correctly, the airflow did increase. However, when I turn the temperature control down during the afternoon heat of 82 degrees, the airflow does not increase.
     
  8. Air_Boss

    Air_Boss Senior Member

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    Does air flow increase when you manually turn the round fan control knob to high? It does sound like there is a flow constriction.
     
  9. Hutch-3

    Hutch-3 New Member

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    No, it does not increase. Were you able to see my previous detailed reply? Thanks Hutch

    I will try to get some photos of the foam piece with the Bore Scope this weekend. Thanks Hutch
     
    #9 Hutch-3, Nov 1, 2024 at 7:27 PM
    Last edited by a moderator: Nov 1, 2024 at 10:46 PM
  10. rjparker

    rjparker Tu Humilde Sirviente

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    He is asking if the fan speed control, using the knob does anything.
     
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  11. Air_Boss

    Air_Boss Senior Member

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    The center knob is multi-function. Thermostat, fan speed, air duct routing selection.
     
  12. bisco

    bisco cookie crumbler

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    maybe the fan speed control is broken, working intermittently
     
  13. Hutch-3

    Hutch-3 New Member

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    Yes, the fan speed seems to adjust by listening to the blower motor sound at all positions. However, it does not allow airflow correctly at all positions. I can hear the fan blower change speeds as I adjust the dial. Again, the system works correctly when the ambient temperature is cooler and not when it is hotter outside.
     
  14. Hutch-3

    Hutch-3 New Member

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    Yes, the fan speed seems to adjust by listening to the blower motor sound at all positions. However, it does not allow airflow correctly at all positions. I can hear the fan blower change speeds as I adjust the dial. Again, the system works correctly when the ambient temperature is cooler and not when it is hotter outside. Here are some photos I took with the Endoscope showing the questionable foam and one of the doors in different Modes.
     

    Attached Files:

  15. Hutch-3

    Hutch-3 New Member

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    I can hear the rpm's change when selected..
     
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  16. Hutch-3

    Hutch-3 New Member

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    Hmmm, that may be an idea. Not sure how the enter workings operate. It may be possible a component has gone bad in part of the switch.
     
  17. Hutch-3

    Hutch-3 New Member

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    When the system is working incorrectly during the Hot day. It is almost like a "Box Fan" pressed against the wall. You hear the noise, but minimal air is being forced through.
     
  18. rjparker

    rjparker Tu Humilde Sirviente

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    You either have to do the tests per the manual or take it apart for visual analysis.

    It certainly will not change fan speed by simply reducing the temp setpoint when not in Auto.

    If it has foam dislodged you won’t get proper airflow and or proper damper operation.
     
  19. bisco

    bisco cookie crumbler

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    perhaps the motor speed is increasing and the fan is slipping on the shaft when hot
     
  20. Hutch-3

    Hutch-3 New Member

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    << Very good point about the foam. = Like.