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Not able to get high a/c fan output while driving.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by JeremyAndACat, Jul 16, 2024 at 4:57 PM.

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  1. JeremyAndACat

    JeremyAndACat New Member

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    When I start my 2011 Prius I can usually get the highest fan speed going while it's in park but once I start driving it will put out air closer to a low or medium speed and I can hear/feel it fluctuating up and down. If I put the car back into park I can eventually get it to put out high speed air but it takes a few minutes. I suspect it's a bad blower motor and/or resistor but the fluctuating up and down only while driving isn't a symptom I'm seeing others experiencing. Any idea what this could be?
     
    #1 JeremyAndACat, Jul 16, 2024 at 4:57 PM
  2. JeremyAndACat

    JeremyAndACat New Member

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    I should add that after about 25 minutes of running, the A/C seems to work normally.
     
    #2 JeremyAndACat, Jul 16, 2024 at 6:03 PM
  3. JeremyAndACat

    JeremyAndACat New Member

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    And sometimes if I set the fan to the lowest speed for about a minute, the issue will be resolved.
     
    #3 JeremyAndACat, Jul 16, 2024 at 11:19 PM
  4. ChapmanF

    ChapmanF Senior Member

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    Is the "auto" light on, or off?

    Does the blower speed bar graph on the display go up and down with the actual blower speed, or is the bar graph staying at full?

    Prius hasn't ever used a blower resistor, though gen 1 and 2 used a separate electronic controller that mounted in the air duct the same way an old-school resistor would, and sometimes people call it that.

    Gen 3 moved that controller into the motor itself, so there isn't even the thing-people-called-a-resistor. At least that reduces the number of parts to think about.
     
    #4 ChapmanF, Jul 17, 2024 at 12:38 PM
  5. JeremyAndACat

    JeremyAndACat New Member

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    The highest fan speed fluctuates whether it's in auto mode or not. The fan speed goes up and down incrementally with the bar graph but the speed still fluctuates up and down.

    That actually is good news about the resistor, thanks!
     
    #5 JeremyAndACat, Jul 17, 2024 at 4:26 PM
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