Acura MDX SUV Forums banner

Rattling Center Dash (Heater A/C Air Mix Motor)

101K views 31 replies 25 participants last post by  mikekowalewski007 
#1 ·
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 :eek:. 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 :).
 
See less See more
1 20
#7 ·
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
 
#8 ·
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!
 
#9 ·
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.
 
#11 ·
Worked on 2005 Honda Pilot

This worked on my 2005 Pilot.

I broke two large clips, one of the side electric port connection clips and the white clip holding on the large wheel gear....ouch! The worm gear was fine and not comming off the drive pin. The real culprit was the contact pins under the big wheel gear. There was some slop play in it when I moved it. This caused an electric short and I think was the reason for the motor twitching. The contact pins all had black sooty grease on them. They cleaned easily with cotton swabs and alcohol. I then slightly bent the pins upwards in hopes of making a tighter contact and to remove the slop play. Next I cleaned the black rings on the back of the large wheel gear the same way. Again, I found more sooty grease. . I re-greased and put it back together using only three workable clips and used some super glue gel inside the white gear shaft where that pin broke. In hindsight, I would drill and tap the outside gear and shaft to use a small set screw in case I needed to clean the contacts again. I fear I won't be able to get back in there now. The other ouside clips that broke ended up being no issue. Because of the sandwitch design of the unit, the three mount screws will easily hold the unit togerther once installed.

Once together, no more twitching!! Hope this helps someone like this thread helped me. Saved over $300
 
#12 ·
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.
 
#13 ·
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!
 
#15 ·
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.
 
#16 ·
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.




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.
 
#17 ·
Fixed Mod Motor Issue - Thanks

I know I'm late to the party but I just used this information to fix my modulating motor controlling the air mix / blend door in my 2005 MDX. I've been putting up with the constant motor position cycling noise that you can hear from the dash. I looked at a lot of threads and this one was the best mainly because of the clear pictures and how of how to remove the arm from the big gear. Thanks! I had a lot grease on the spring loaded contacts and after a through cleaning of everything and a light re-lube, the motor module is working great. Thank for saving me some time and frustration trying to figure it out myself.
I would add one thing, although I feel it is a good idea to mark the pieces for reassembly, it seems to me that the motor self-aligns itself via the computer resistance signal, not an indexing mechanism. So exact positioning during reassembly isn't necessary.
Thanks
 
#18 ·
Hey folks,

so I designed a new replacement pcb for the air mix motor. I had 25pcs made at a pcb fab house with resistive traces and I've been using it in my wife's Pilot for a year now. I haven't heard any clicking or anything behind the dash. The old pcb had worn through around the 70F mark, which makes sense. The new pcb might not be 100% correct though, as I was guessing at the resistance amount and I don't know if the fab house followed my instructions 100%, as the pilot now seems to be maybe 10F off? I'm not sure if that's even right as I don't drive it very often and the wife doesn't pay attention :p

In summary, the pcb works great but the actual temp numbers *may* be wrong (ie, if you put the dash to 70F, the cabin might be 75F, so we've learned to adjust the temp to lower than what we actually want).

Anyone wanna try one out? $25 shipped. pm me.
 
#30 ·
Hey folks,

so I designed a new replacement pcb for the air mix motor. I had 25pcs made at a pcb fab house with resistive traces and I've been using it in my wife's Pilot for a year now. I haven't heard any clicking or anything behind the dash. The old pcb had worn through around the 70F mark, which makes sense. The new pcb might not be 100% correct though, as I was guessing at the resistance amount and I don't know if the fab house followed my instructions 100%, as the pilot now seems to be maybe 10F off? I'm not sure if that's even right as I don't drive it very often and the wife doesn't pay attention :p

In summary, the pcb works great but the actual temp numbers may be wrong (ie, if you put the dash to 70F, the cabin might be 75F, so we've learned to adjust the temp to lower than what we actually want).

Anyone wanna try one out? $25 shipped. pm me.
You guys are awesome! 2006 MDX TOURING Took mine apart. The worm gear was tight but the contacts under the large gear were filthy. Cleaned, lubed and reinstalled. NO MORE NOISE! THANK YOU!
 
#19 ·
Just registered to say thank you!!! I just did this fix on my 2005 MDX and everything went perfectly. I had been hearing the noises for about a year and thought they were coming from the CD changer. There's no way I would have attempted this without the detailed pictures and instructions. For me, the contacts were pretty clean, but there was play in the worm screw. Great tips too; I also just used a screwdriver to pry the compression fitting away from the motor.
 
#22 ·
12 Blue X (OP)

This was a great post about fixing the blower motor assy on the MDX. Unfortunately, your pictures are no longer available. Can we trouble you to repost?

Thanks so much

Dave Marzo

PS Since I am so new, I cannot send a PM to 12 Blue X. If anyone is willing to do it, I think he is still active on the boards
 
#23 ·
It worked!

Thanks for the post. I couldn't have done it without it.
Just wanted to clarify a couple points. My apologies if it's already been stated.
1. It's easier to disconnect the metal rod on the far flange, as opposed to the near flange on the servo assembly. My far flange connection had little white plastic clip that I pushed off the rod with my fingers. Then the rod lifted right out of the hole.
2. I warmed up the fragile locking clips on the clamshell with a blowdryer to make them more pliable. I slowly worked the shell apart with plastic trim clip removal tools. Thought I was so smart, didn't break any, until I noticed I had missed the clips on either side of the plug They were busted, ha ha!
3. I cleaned off the contact grease under the big wheel and regreased with Permatex dielectric grease from Pep Boys. Whoever assembled the servo put way too much grease on. Anyways, it had turned black, probably from erosion of the copper contacts. I suppose this degrades the signal.
No more hamster-on-a-conveyor belt sound! Every push of the up/down temp arrows is accompanied by immediate small adjustment of flaps. So awesome! Thanks a million.
 
#24 ·
Thanks for the post. I couldn't have done it without it.
Just wanted to clarify a couple points. My apologies if it's already been stated.
1. It's easier to disconnect the metal rod on the far flange, as opposed to the near flange on the servo assembly. My far flange connection had little white plastic clip that I pushed off the rod with my fingers. Then the rod lifted right out of the hole.
2. I warmed up the fragile locking clips on the clamshell with a blowdryer to make them more pliable. I slowly worked the shell apart with plastic trim clip removal tools. Thought I was so smart, didn't break any, until I noticed I had missed the clips on either side of the plug They were busted, ha ha!
3. I cleaned off the contact grease under the big wheel and regreased with Permatex dielectric grease from Pep Boys. Whoever assembled the servo put way too much grease on. Anyways, it had turned black, probably from erosion of the copper contacts. I suppose this degrades the signal.
No more hamster-on-a-conveyor belt sound! Every push of the up/down temp arrows is accompanied by immediate small adjustment of flaps. So awesome! Thanks a million.
Thanks for this! By chance, do you have access to the pictures that were provided initially but are no longer accessible on this site?
 
#26 ·
Thank you so much for posting the archived pictures. Very helpful. With help of friend, I was able to do the repair today. I had similar problems (that darn rattle; having to turn knob to 60 to get cold air) and this repair was the fix I needed. Thanks to all who have posted with thoughts. Saved me a ton of money. Thank you

(Skirmich - were you able to fix your issue?)
 
#28 ·
Whatever you do, don't buy this replacement unit if you drive a 2005 MDX:

(link removed - moderation)
AutoZone Santech 95229_0_33846

Everything seems fine, except the plastic shaft is actually coming out of the wrong side! No way to reverse it either, that shaft is integrated with the big gear and can't be flipped around, sadly.

Alex
 
#29 ·
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 :eek:. 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 :).
 
#31 ·
12BlueX and all the dudes, thanks for the original posts. your guys are awesome.
I followed the lead and fix the noise problem for my 2005 MDX. the noise indeed is from the motor assembly. in case anyone couldn't fix the motor, you can go to EBay to get a new one for around $20 (not the OEM of course). just type 604-946 which is the Dorman number for Honda 79160-S0X-A01. I will keep the old motor going and if it breaks down, then I will get a new one.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top