2006 impala has clacking noise under the dash.

persevere1persevere1 Member Posts: 10
edited June 2014 in Chevrolet

I dis-connected the power to both the fresh air and recirculating actuators, but the clacking noise remains. What else could be causing the noise ?


Best Answers


  • persevere1persevere1 Member Posts: 10

    I forgot to mention that heat and cooling work fine. Also the noise is only at the beginning of a
    trip and at the end of the trip, and lasts for 30 to 45 seconds and then stops clacking.

  • persevere1persevere1 Member Posts: 10

    Yes, very helpful imidazol97...I think it is # ! BUT I was not able to locate this part at rockauto using the description of mode actuator. Any ideas how I can find this part ? Also is it a big job
    to install ? Thanks again for your help...Angelo

  • persevere1persevere1 Member Posts: 10

    imidazol97. I did find this part at GM parts pros for $32.29. They call it a mode valve and it is also associated with the blend door. It looks like it is next to the blend door actuator. So hopefully it is not too difficult to replace. However I now found out there is a 4th actuator on the driver's side that would require removal of the HVAC unit. That is a big job. Maybe 4 hours for an experienced mechanic with all the necessary tools. I guess I'll find out after checking out
    the mode valve. Have you heard that a stuck door can also be the culprit ? And would you know
    how to get it un stuck ? Or is that a big job too ??

  • imidazol97imidazol97 Member Posts: 26,752
    edited June 2014

    ACDELCO Part # 1574123 {Click Info Link for Alternate/OEM Part Numbers} GM Original Equipment
    Mode Door Actuator

    Part Image

    I found what I think is the right one. It's in the 3.5 L engine? 2006? Impala? and Heater and Air conditioning group.
    Then click on Heater Blend Door Actuator.

    I have an advantage knowing that on rockauto.com these actuators sometimes end up in wrong groups/labels because of the similarity--that can include the vacuum diaphgram from earlier heaters which are also actuators (not electric).

    Take a really good look at the picture to be sure it matches the shape of the one you have. And take a a good look at how it comes out. Does the nearby actuator interfere and have to be removed first?

    Also, can you have someone operate the controls if needed while you touch the actuator (use a dowel or screwdriver) to actually feel the vibrations are coming from it? Lots of parts of have been replaced when they're not the cause of a problem. So try to verify.

    This page has two pictures and a list of parts numbers that are all the same piece.

    Good luck.

    2014 Malibu 2LT, 2015 Cruze 2LT,

  • persevere1persevere1 Member Posts: 10

    THANKS AGAIN !!! There is a plastic shroud that is hiding this part from view. I can see the blend door actuator, but then the plastic shroud is in the way. I think I can cut away a piece of the shroud and be able to see the mode valve and also assist in it's replacement if that is the culprit. You're GREAT...Thanks for all the advice !!!

  • persevere1persevere1 Member Posts: 10
  • imidazol97imidazol97 Member Posts: 26,752

    Do you have dual air temperature controls? Separate for passenger blend door? That's what the other actuator is on the right side of the unit for the passenger blend door.

    2014 Malibu 2LT, 2015 Cruze 2LT,

  • persevere1persevere1 Member Posts: 10

    Yes, It is a dual zone unit..I will keep you posted on my progress or non progress after I get back to try some of your great advice. Un fortunately the car is not available to me as often as
    I would like. Thanks again....

  • persevere1persevere1 Member Posts: 10

    I checked out the mode valve by placing my hand on it while the clacking was happening, and it was as quiet as a church mouse. Also the clacking came from near the center of the dash or even more towards the driver's side. And since the other 2 actuators (passenger blend door and recirculating actuators have been disabled by removing the power (CONNECTOR), that leaves only the driver's side actuator as the culprit?? I think I will have to take it to the repair shop to have the unit removed in order to replace this actuator. I am not about to attempt this job on my own..I wish that Chevy would have provided a drop down connector from this actuator so that
    the power could be disabled from this actuator. Then I would have been happy to just have the passenger side working and be able to get rid of the noise. The noise only lasts about 35 seconds, and I would put up with it. But others that use the car or get in to ride in the car are frightened that the car would break down and then they would be stranded.
    Also I thought I read somewhere that the clacking noise might be corrected by using a good scanner and recalibrate or synchronize the system. Does anyone out there know if this is possible ?

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