AC goes 'CLUNK' when shut off

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Gdngrn, Aug 15, 2025 at 4:26 PM.

  1. Gdngrn

    Gdngrn New Member

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    My 2007 Prius just had a new air compressor installed at my Toyota dealership. On the way home (over 150 miles), a tractortrailer tire exploded in front of me on the highway and ate up the front of my car. My local auto body fixed it all up but now when I shut the AC off before turning off the car, after a few secinds, I hear a loud 'CLUNK' from behind the glovebox area. The autobody man assures me that's the normal sound of the compressor closing its 'door' when I shut it off. Is this right? I didn't turn off the AC at all before the accident so I don't know if the CLUNK happened prior to it. Ty everyone
     
  2. Tombukt2

    Tombukt2 Senior Member

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    More than likely it is the damper door moving. But I forth think they have a dedicated rest position. As motor wears the unit hunts for the selected position
     
  3. Gdngrn

    Gdngrn New Member

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    Is this sound a sign something needs to be fixed, then? Ty.
     
  4. Tombukt2

    Tombukt2 Senior Member

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    If it's the damper door hunting no it's just irritating. But for some reason I don't think this is the problem
     
  5. Gdngrn

    Gdngrn New Member

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    You think something else is causing the sound?
     
  6. pasadena_commut

    pasadena_commut Senior Member

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    Cars normally have 3 climate actuators. The first controls where the air comes out (dash, feet, window) and had 3 or more distinct positions. The second controls the temperature mix (hot to cold) and is continuously variable between two end points. The third controls the intake air mix (fresh/recirc) and is either all the way open or all the way shut. The third one is almost always right next to the cabin blower behind the glove box, and can make a thunk when it lands at one end of its range or the other. Take the glove box out and toggle the refresh/recirc and see if you see a flap moving, and if so, see if it makes that noise.

    I wouldn't expect front end damage to change the sound of any of the actuators unless said damage made it all the way into the cabin.

    The compressor itself doesn't have any doors. It is hooked up to pipes full of refrigerant. I suppose it is possible that one of those pipes might clunk against something when the compressor turns off if one of those pipes is not correctly attached at all of its support points.