Rattling Center Dash (Heater A/C Air Mix Motor) - Acura MDX Forum : Acura MDX SUV Forums
 
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post #1 of 15 (permalink) Old 11-17-2012, 02:20 PM Thread Starter
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Rattling Center Dash (Heater A/C Air Mix Motor)

I have a 2004 Acura MDX. When I have the A/C or Heater on, I hear the rattling sound from center dash, Glove compartment area that was really annoying. The sound goes away once I turn the A/C or Heater off. Also, my A/C didn't feel so cold or heater didn't feel so hot regardless of the temperature setting.

So I decided to trouble shoot by listening for the sounds along with some research on the internet. I found the problem to be heater air mix motor. This unit moves the flaps back and forth to control the flaps in the vent for cold and hot air.

So as usual, as the part looks like it's easy to replace, so I went to OEMacuraparts.com to see what this part is and how much it costs which was identified to be 79160-S0X-A01 MOTOR ASSY., AIR MIX $278.98 list price . Even with Tim's discount, it's still over $200 for this stupid small plasticky thingy so I was determined to find another option. I thought of getting a part from the junkyard/ebay but I figured it's likely to have a same issue.

Then I came across this posted by 1947froggy on youtube.

The part was exactly the same as the Lexus and at the end, I believe this solved my problem. Here's some step by step guide for my 2004 MDX which saved me at least $200 in parts alone (sorry Tim!).

As usual disclaimer, I take no responsibility if you decide to use this information. Working on cars always has inherent risk and it's easy to hurt yourself or damage the car. You're using this information at your own risk.

Before I started anything, I turned on the car and the A/C and set the temperature to the lowest setting (60F). Then I turned off the A/C and the car. I did this so that if I screw up the swivel position (you'll see what I mean below), I have a reference point.

I took the passenger side center console panel off.


If you then crouch down and look towards the center consol, you'll see the air mix motor.


Unplug the green connector and then take the rod off from the white swivel with black hinge. This was bit tricky but I used a small screw driver between the black hinge and the rod to pop it off. The picture shows after I manage to take the rod off.


Remove the passenger floor light which is held by one 10mm bolt. Don't forget to disconnect the white connector (looks grey in this picture).


Remove the 3 bronze screws from the air mix motor and it will come right off.





Now this is a good time to mark the position since this swivel is indexed. I marked at the arrow position along with other areas using silver sharpie for good measure.







Now time for disassembly of the air mix motor. There are several tabs that are holding the covers together. This tab is very delicate so you should use your screwdriver gently and only bend until it clears. I used folded paper as a wedge to work this through and managed to not to break any.





The inside look like this. This is now a good time to mark the top part of the motor, just in case the motor is sensitive to polarity (I don't think it is but just in case).



Now the problem is the worm screw that you see on the picture and the youtube link which specifically explain this issue. I've also read somewhere that the big wheel contacts can also cause problem so I decided to take the big wheel off. Again, before taking the big wheel off, mark the position with your extensively used Sharpie.



The big wheel is secured by the white swivel on the back side with a tab. Now this tab is also very sensitive and it can break. I think I may have created a hairline crack in the process but managed not to break it all the way. Reinforced the tab with superglue and it seems to be fine.



Big wheel is off.





I cleaned the back side of the wheel and contact points with Q-tips and rags very gently. I then regreased them with dielectric grease. I happened to have SuperLube from my suspension work so I used it.



I then reassembled the big wheel and tackled the worm gear. I did exactly as the youtube described accept I ended up using the screw driver to nudge the compression fitting instead of the hammer, plier, and vise. I also made sure there's enough grease at the end of the worm gear and that the it rotates freely while still being snug so that there's no movement. I also cleaned up some of the other gears and regreased them with SuperLube.



I then check all the positions of the parts (motor, big gear, and the white swivel), made sure everything is aligned, and then snapped the covers back together.

I know some suggests to connect the motor to test but since I didn't want to mess with the positions, I just installed it and tested it before I put the floor light and the console side panel back on.
What I also did, which may not be necessary, is to lightly greased the white swivel at the center panel pictured here and also greased the metal rod.



When installing, make sure the metal rod sticking out of the swivel is aligned/connected to the swivel on the center console.



I also found it easier to screw at least one on the air mix motor before you connect the long rod to the black swivel.

Then complete all the screws and connect the green connector.
Then turn your A/C on and change the temperatures.
If all is good, you'll see the motor moving the swivels without making any significant noise.

If all is good, install the floor light with the 10mm bolt, connect the wire to the floor light, and then reinstall the center consol panel.

Since I did this today, it may be early to tell but the sound I can hear regularly when set at 70F to 72F is completely gone.

Now I have extra $200+ to spend on something else .

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post #2 of 15 (permalink) Old 11-18-2012, 11:48 AM
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Great write up. My 03 has the same rattle! thanks for posting.
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post #3 of 15 (permalink) Old 11-18-2012, 01:43 PM Thread Starter
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Quote:
Originally Posted by poolpartysrule View Post
Great write up. My 03 has the same rattle! thanks for posting.
You're welcome!

I've had other members help me on things like engine mount so I have no problem contributing back.
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post #4 of 15 (permalink) Old 11-18-2012, 04:24 PM
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Great write up! I have been using Silicone spray on the swivels and levers where they connect to unit while still mounted under the dash. One or two good blasts. Low odor.
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post #5 of 15 (permalink) Old 10-21-2013, 04:34 PM
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Great write up. Thanks a lot.
After assembling everything back, noise is gone, but no hot air What did I do wrong? Please help.
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post #6 of 15 (permalink) Old 10-22-2013, 12:22 PM
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It turns out to be a user error. The rod came out during installation. After connecting it back, everything works as expected.
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post #7 of 15 (permalink) Old 12-06-2013, 01:58 AM
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Bravo! Bravo! Bravo!

12BlueX, you are a Gentleman & a Scholar.

I had the same problem on my 2006 Pilot LX.
My problem was not the worm gear, but the position tracks under the big wheel.
I cleaned them up and now the servo does not make that annoying noise anymore.
It moves back and forth smoothly. Which it makes sense if the tracks are dirty, the A/C control can't lock on the position of the actuator arm/wheel.

You just saved me $200+

Happy Holidays!

Hectorb
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post #8 of 15 (permalink) Old 02-07-2014, 09:33 AM
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Great Post

My 05 MDX had the rattling sound for some time. Then I could only either freezing cold air (Set at lowest setting) or roasting hot air (any other setting). This post allowed me to repair the air control motor to eliminate the rattle and it fixed the temperature problem as well!

A small mirror made this job a lot easier, the location of the motor was a little difficult to see without a mirror. I used light bulb grease to lubricate the motor, seems to work fine.

Thanks again for the post!
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post #9 of 15 (permalink) Old 03-05-2015, 11:19 PM
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I had the same issue with this motor in terms of rattling sounds under my dash on MDX 2007.
But worm screw was tight enough and I believe the issue was with the lubrication on the contacts on the biggest wheel which is used to measure angle by resistance. In my case contacts were covered with the white lube which leaked on that surface during some hot day in Texas where my MDX came from and become hard with regular temperatures.
Let me explain.
The on-board electronics starts rotate the cover to the certain level measuring the resistance to understand the current position. During the rotation the hard lube detached the contacts from the contact surface and controller has an impression that the angle is wrong and changes the rotation direction. As you can get on its way connectivity gets back and the whole story happens again, and again....
I cleaned up the contact surface of the big wheel and assembled everything back. Now it works fine.
So take this into consideration.
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post #10 of 15 (permalink) Old 04-23-2015, 11:03 PM
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How did you get the air mix motor out?!?!?

Quote:
Originally Posted by Dragon31337 View Post
I had the same issue with this motor in terms of rattling sounds under my dash on MDX 2007.
But worm screw was tight enough and I believe the issue was with the lubrication on the contacts on the biggest wheel which is used to measure angle by resistance. In my case contacts were covered with the white lube which leaked on that surface during some hot day in Texas where my MDX came from and become hard with regular temperatures.
Let me explain.
The on-board electronics starts rotate the cover to the certain level measuring the resistance to understand the current position. During the rotation the hard lube detached the contacts from the contact surface and controller has an impression that the angle is wrong and changes the rotation direction. As you can get on its way connectivity gets back and the whole story happens again, and again....
I cleaned up the contact surface of the big wheel and assembled everything back. Now it works fine.
So take this into consideration.

How did you get the air mix motor out. I have 2007 MDX.
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post #11 of 15 (permalink) Old 09-05-2015, 11:26 AM
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Many thanks to 12BlueX for the step by step and froggy for the video. You guys are beyond awesome.

A little background information. I did a google search for "2006 MDX chattering noise." This is how I described it. Miraculously, this was one of the hits in google. I first played the video and this was the identical sound I was hearing.

So I planned this repair on a cooler day but could not wait so I did this in 80+ degree weather in my garage. The instructions were spot on. The only difference for me was removing the metal rod. What I ended up doing was using my bare hand and use my fingers to twist the plastic retainer out and the rod popped out. It was tricky this way too but it worked for me.

I too broke one of the tabs (one of the ones on the side of the plug) even after being super careful. I used cardboard pieces as the wedges.

Thank you again 12BlueX and froggy for taking the time to do what you did.
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post #12 of 15 (permalink) Old 10-14-2015, 01:15 PM
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Well I went ahead and did this fix 2 days ago. I didn't see anything damaged so I'm guessing the build up of dirty grease may have been the culprit? It seems to be working normally now. I've replaced this part about 5 yrs ago for the same issue and it was going crazy with the temp for about 4 months now. Hopefully this works and if so you'd be an idiot not to give it a try first, it's so easy!
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post #13 of 15 (permalink) Old 10-15-2015, 01:17 PM
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This really is a great DIY. Sometimes the best way to save money on a repair is looking at it and saying "well, it's already broken, so what's the harm in trying?"

That's kind of how I've started on many of my hobbies

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post #14 of 15 (permalink) Old 05-21-2016, 10:02 AM
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I have a quick question in regards to this posting, if I get cold air to the passenger side, but only Hot air to the drivers side, would this be a cause of the issue. I get both hot and cold air, just not on the drivers side, I only get hot air on the drivers side of the vehicle. It's a 2007 MDX. I'd love some input on this before I start taking things apart.
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post #15 of 15 (permalink) Old 05-25-2016, 08:14 AM
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2004 MDX Air Mix Motor REplaced

I had this issue in my 2004 MDX. The clicking noise has driven me crazy for a year but the dealer wanted around $500 for the repair. Also the ventilation would blow only hot air unless the temperature setting was turned all the way down so that it would blow only cold air - there was no middle ground and no automatic switching. I found an ad for a remanufactured Air Mix Motor on eBay for $95 and chose the go that route so all I'd have to do was swap the unit and not repair it.

I used some of the photos and information posted by OP to remove the old unit and was able to swap in the new unit immediately. The only difficult part of this was working in such a cramped area under the dash. First thing for me was to pop the side panel as shown in the second photo and then remove the light. I left the light hanging there and used it rather than a flashlight by moving it around as needed. In the end everything worked fine. It was a little difficult as I'm a big guy. If there was easier access to this area it would be super easy.


Quote:
Originally Posted by pthompson7 View Post
I have a quick question in regards to this posting, if I get cold air to the passenger side, but only Hot air to the drivers side, would this be a cause of the issue. I get both hot and cold air, just not on the drivers side, I only get hot air on the drivers side of the vehicle. It's a 2007 MDX. I'd love some input on this before I start taking things apart.
See my description of my issue above. It was different from yours. I also just checked the ebay ad where I bought my remanufactured part and the part I bought is not compatible with the 2007 MDX so the part and the way it works might be different.
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