Knocking noise under dash

robert220robert220 Member Posts: 1
edited July 2015 in Chevrolet
I have 2006 impala, when running the air after i turn off the car i hear a knocking noise under the passenger side dash, any ideas what it could be.

See Also
Chevy Blend Door Actuator Replacement


  • tschutztschutz Member Posts: 4
    When it is damp outside, my 2007 Chevy Impala when you use the signal lights it has a buzzing sound under the dash each time the signal light flashes, it does it right or left.
  • djf5djf5 Member Posts: 1
    I have a 2007 Impala and after turning off a/c, knocking noise for about 30-45 seconds. I looked behind the glove box and saw this white box going up and down after turning off the a/c. Repair shop said it's an Actuator that's tied into the lend door that controls the air/heat. Got it repaired w/ parts/labor for $200. Hope this helps.
  • pooadridpooadrid Member Posts: 1
    I have a 2007 Impala and after turning off or turning the a/c, knocking noise for about 30-45 seconds or more. i opened up the glove box and removed some papers that were blocking the air flow.

    And of course this noise only happens every now and then but when it does. wow is it annoying.

    so of course when i finished cleaning out that area it didnt make any noises. which i figured that fixed the problem....but it didnt.

    it continues again. and this sound shifts from driver side to passenger side. sometimes though.

    so what should i do?
  • needcarfixedneedcarfixed Member Posts: 1
    Hello, I was trying to find out where the acuator is located because my car is doing the same thing and I was told by the dealer that it sounds like an acuator but it would cost me 7 or 800 dollars to fix. Any suggestions
  • rob771rob771 Member Posts: 2
    Having the same thing going on with my 2008 Impala LS at 42,000 miles. If I turn the fan speed up (with the outside air option LED lit) and press the snowflake (to kick on the compressor) it doesn't make the knocking noise. Switch the air from outside air to recirculate and I hear the knocking noise from under the dash. Eventually the noise stops (after 30-45 seconds). When I turn the fan speed back to Lo, the knocking noise returns (probably because it's switching back to outside air). It's probably the actuator. Spoke with one of my neighbors who mentioned having that problem on a Chevy pickup.

    Already had the steering issue/bumping noise when you accelerate/decelerate. Thankfully, that was fixed under warranty.

    Last year I had the problem where I had no heat the first cool spell. That ended up being another trip to the shop.

    Just today I ran into the alignment problem/premature tire wire.
  • dosj65dosj65 Member Posts: 6
    My 07 is doing the same thing. I was told it is the arm control valve. Though it is annoying it's not a major problem. If I am wrong please let me know, I hope to be able to wait a while to get mine repaired.
  • dosj65dosj65 Member Posts: 6
    My 07 Impala's trunk release inside the car and on my remote has stopped working. I did not realize that there is not a key spot on the outside of the car as a back up. Any ideas what is the problem?

  • ctaylor63801ctaylor63801 Member Posts: 1
    :mad: Knock knock, tic tic, knock knock! Wow so you have heard this as well? So glad you did because you see I took my car my 2008 Impala back to the dealership I bought it from Sikeston Autry Morland, and the service manager told me i had a problem with my battery, that once that was replaced I wouldnt hear this noise...I argued with him till I was yelling and blue in the face! Telling him there is no way this was my battery! I purchased a new battery took the car back up to him and since I belittle and ashamed him I was kicked off the premises. Now my car is at a different location being fixed....
  • dosj65dosj65 Member Posts: 6
    Gosh, hated that you had to spend money on a battery. My only does it when I turn off the ac, my husband says it the control shutter door (something along those words lol) if I turn my ac back on it stops. I have used my heater a little and it does not do it at all. Unless you are using your ac all year, I would probaly wait to get it fixed.
  • dosj65dosj65 Member Posts: 6
    I got my trunk fixed, after I had several people it was going to cost quite a bit to fix it. My husband pulled the fuse out and replaced it with a new one. The trunk and remote are both working fine now.
  • bobby80908bobby80908 Member Posts: 1
    My Pontiac Vibe started making a clacking noise (about 2/sec.) but stops when I turn off the outside air. The A/C is off. When I stop 'Inside Air' so it brings in fresh outside air, it takes about 5 seconds and the clacking noise starts again.
  • elkparkerjmpelkparkerjmp Member Posts: 2
    My mechanic immediately diagnosed, "Actuator!" when I described the knocking noise under the dash of my 2006 Impala. He recommended waiting until the heat/air no longer works before springing for the repair, and explained it won't be a cheap fix -- about $500 "because the dash has to come out". Although the racket is annoying, it only occurs when I turn off the engine -- and not every trip -- and usually winds down by the time I've climbed out and locked up.
  • daves95maximadaves95maxima Member Posts: 1
    In the Impala all the mechanic has to do is drop down the glove box door and the actuator is right there and held on by 3 6mm screws very easy fix!
  • dosj65dosj65 Member Posts: 6
    Thanks for the info! Definitely not spending several hundred $ to fix a 60 second noise and then it stops.
  • dosj65dosj65 Member Posts: 6
    My 07 Impala's message center keeps flashing that the trunk is open. It started several weeks ago & yes the trunk is closed lol. Could this be a fuse that needs replacing?
  • gmcustsvcsarahgmcustsvcsarah Member Posts: 1,964
    You can find information on your vehicle's electrical system (including diagrams of fuse blocks) starting on page 397 in your owner's manual. If we can be of any assistance, please let us know!

    GM Customer Service
  • goldi1goldi1 Member Posts: 1
    I just recently discovered this knocking sound in my 2008 Chevy Impala, I was told by a friend that this is something she heard in a similar car. Is this something that I can fix or is it best to have a mechanic do it? its started to get louder and sounds like now its in the venting and the dashboard! Help!

    Damsel (IN DISTRESS!!!)
  • luckygirl7133luckygirl7133 Member Posts: 1
    My 2006 does it, but it has gotten worse. Now it won't stop unless i turn the car off and it takes about 5 minutes before it does stop. And only HOT air blows out of my driver's side vents.
  • gmcustsvcsarahgmcustsvcsarah Member Posts: 1,964
    Good evening luckygirl7133,

    We're sorry to hear that you're having some troubles with your HVAC system; what are your plans for getting this looked into?

    Sarah, GM Customer Service
  • chandrab1chandrab1 Member Posts: 1

    I am into a month or so now. The knocking noise under my front passenger dash is scary especially traveling with young children. I spoke on the phone and via email with a GM customer service representative who recommended that I take the car for a diagnostic at Sport Chevy in Maryland-Bad Idea!. They diagnose the car as the REAR Actuator which I am unable to understand because the problem is when I switch from vent to AC that knocking sound gets louder. They wanted $405 to fix that problem but wouldn't discount it from the $113. diagnostic fee I had to pay. I am so frustrated because this is a very common problem with Chevys and for them to put it onto the power train warranty but not upheld their part of repairs is just ridiculous. An obvious problem. I took my car to a local shop and they will fix it for $200. And I found out that the car is leaking engine oil onto the transmission which I am told could caused a fire. GM would have plenty to worry about then. I am so disappointed and do not think I will every recommend or purchase another Chevy vehicle for that matter.
    Disappointed at their customer service
    Chevy Impala 2008 Owner

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