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Periodic Clicking Noise Emanating from Behind Passenger Side Dash

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by BentSpace, Oct 30, 2019.

  1. BentSpace

    BentSpace Member

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    The noise happens when the car on, even with the A/C, the stereo and the ICE off. Eventually when I drive for awhile sometimes the noise will go away.

    When I tried to locate it, it sounds louder inside the car, rather than under the hood and seems to be coming from the passenger side dash.

    I'm trying to attach a sound recording of the noise that I made with my iPhone, it's a .m4a file, but can't seem to figure out how to do that...

    Any ideas what the noise could be?
     
    #1 BentSpace, Oct 30, 2019
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It probably is one of the three servo motors associated with the heating/ventilation/air conditioning system. Fresh/recirculate, dash/floor, and cold/hot mix are the three air paths that need motor control.
     
    #2 Patrick Wong, Oct 30, 2019
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  3. BentSpace

    BentSpace Member

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    Okay, so had to take a video of my computer playing the noise, it was the only way...
     
    #3 BentSpace, Oct 30, 2019
  4. BentSpace

    BentSpace Member

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    Interesting, would it be making noise even when the A/C system is off?
     
    #4 BentSpace, Oct 30, 2019
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    When you turn off the HVAC system, you are pressing an icon on the multifunction display or pressing a button on the steering wheel. Either action is only making a request to the air conditioning amplifier to power down. The power is not actually cut. Hence, the AC amplifier is trying to set the servo motors to the positions deemed resting when the AC system is off.

    If a motor does not reach the desired position or if the associated position sensor is not working right, the AC amplifier is going to keep trying and the result is the clicking noise.

    More importantly, what are you going to do about it? Depending upon which motor is having trouble, it can be extremely difficult to reach without totally taking the dashboard apart.

    I recommend you turn the stereo up a little louder and ignore the clicking noise. It might go away eventually, or the motor might fail at which time you can be motivated to spend the $$$ to have it fixed.
     
    #5 Patrick Wong, Oct 30, 2019
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  6. BentSpace

    BentSpace Member

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    Hopefully it will go away... Was planning to sell the car next spring.

    Is there anyway to find out for sure that's what the noise is, or are you pretty certain?
     
    #6 BentSpace, Oct 30, 2019
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Get under the dashboard when the noise is occurring and try to determine where it is coming from. It is highly likely that the noise is coming from a servo motor; those motors, the cabin ventilation fan, and the wiper motor (located in the engine compartment) are the only moving mechanical parts in that general vicinity.
     
    #7 Patrick Wong, Oct 30, 2019
  8. Blox

    Blox Junior Member

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    Curious if this ever got resolved :)
     
    #8 Blox, May 30, 2023
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