2006 Accord, odd noises from dash linked to AC?

[greenjp]

Have a weird one for you guys, want to see if anyone has ideas.

Have a 2006 Accord EX with 118k. No real problems of any kind, best car to this mileage I've had yet.

Recently started noticing a noise, seemingly emanating from within the dash directly in front of the driver's seat, like behind the instruments. It is a strange gurgling/crunching/mechanical clicking sort of sound, quiet enough that normal road noise or the radio drowns it out but loud enough to be quite obvious when idling. The noise is inaudible from outside of the car or from under the hood.

It seems that it might be related to the AC setting - when I set the AC to fully OFF, it will persist for about 30 seconds, then the noise stops. If I turn the AC back on, the noise returns in within a similar amount of time. It does not change with fan speed, which vents are selected, or auto vs. manual settings.

The AC works fine, no problems at all even in the 100 degree temps we had recently.

Any ideas? Given the behavior I wonder if it's something weird happening with the evaporator, but the crunchy/clicky aspect of the sound makes me think of something like a blend door or actuator of some kind going haywire.

jeff

 

[DukeOfFrontenac]

Had this issue on my 2006 Honda Pilot, might be the same thing. Was the 'blend door motor'. Contacts get dirty/worn and the thing winds up hunting for what position it's supposed to be in. Crunching sound just like you described. Search the net for it. Was a relatively simple DIY to repair it.

 

[greenjp]

The power of BITOG! 8 minutes and I think you've hit the nail on the head, youtube videos indicate this is likely the problem. I'll report back if/when I figure it out. Thanks!

jeff

 

[Hokiefyd]

Yep, if you have an automatic climate control, it's probably the air mix door. I've taken that silly motor off our MDX about 5 times and cleaned out the contacts inside. It's a very common problem on the Pilot/MDX. I think I heard similar noises from our 2008 CR-V also.

If you can see the motor, you can watch it twitch the lever back and forth. If you set the system to full cold or full hot, it won't click (because it'll be commanded to full range in either direction). Pretty much any temperature between either extreme can make it click if the contacts in the motor are worn.

I'm cheap and haven't replaced the one in our MDX. Instead, I take it apart every 6 months or so and keep it going. The motors aren't inexpensive.

 

[greenjp]

Thanks for the elaboration, very helpful. Yes it's a rare EX-L with the 4 cylinder and stick shift with ACC.

I've had a bit of trouble finding any decent DIY info or even a good parts diagram to figure out exactly what I need. I find it strange that despite the ubiquity of these cars, info like this is much harder to come by than it was for my Saab 9-5 or my old Suzuki motorcycle for that matter. Honda's own parts site is terrible.

If I understand correctly, this is mounted up under the dash above the accelerator and has some sort of white plastic linkage sticking out of it?

jeff

 

[DukeOfFrontenac]

Originally Posted By: greenjp
Thanks for the elaboration, very helpful. Yes it's a rare EX-L with the 4 cylinder and stick shift with ACC.

I've had a bit of trouble finding any decent DIY info or even a good parts diagram to figure out exactly what I need. I find it strange that despite the ubiquity of these cars, info like this is much harder to come by than it was for my Saab 9-5 or my old Suzuki motorcycle for that matter. Honda's own parts site is terrible.

If I understand correctly, this is mounted up under the dash above the accelerator and has some sort of white plastic linkage sticking out of it?

jeff


For my Pilot it was under the dash, basically dead center. And yes, there was a plastic arm coming out of it connected to a metal rod that links it to the blend door. It was a little tricky to get out but by no means the toughest under dash experience I've ever had. Might be kinda tight in an Accord though. As Jason mentions above it is an expensive part from Honda. I had no problems fixing it for zero dollars and an hour or so worth of time. Good luck!

 

[Hokiefyd]

Originally Posted By: greenjp
If I understand correctly, this is mounted up under the dash above the accelerator and has some sort of white plastic linkage sticking out of it?


Yep. Here are some pics of the last time I did the job on our MDX, with captions following each.

As installed. Ours is accessible through the passenger side floorboard area. Our MDX's climate control's two zones are not split left-and-right as most are, but front-and-back. So the dash has a single zone automatic climate control (with a separate system for the rear). Your configuration in the Accord will likely be a little different.

The box has a plastic arm and also a metal rod, and it operates two air mix doors at the same time. The plastic arm has a metal post sticking up that rides in a track on one of the air mix door's plastic arms, and the metal rod reaches over and operates another air mix door. If yours is the same way, be careful with the plastic clip that fixes the metal rod to the far air mix door. You need to push the plastic clip to the right (in this photo) to unlock it from the air mix door. Then you can gently ease the rod out of that door's arm.

Then, it's four screws to take the thing down.

The actual motor box. Manufactured by Denso.

The bottom of the motor, as installed in the vehicle. You've already removed the four screws; at this point, the only thing holding the case halves together are the plastic tabs along the edges. I've had mine apart so many times, my tabs are all broken and I use a stripe of electrical tape to hold the case together when I'm handling it. When you mount it to the vehicle, the four small screws that mount it also sandwich the case halves together, so it's not an issue if you break some of the plastic tabs.

Inside the motor. You need to get to the other side of that large plastic gear, which is where the electrical contacts are. So you need to remove the plastic arm.

To do that, use a small flathead screwdriver to move the small retaining tab in the motor shaft. Then you can to pull the plastic arm straight up off the motor shaft.

Like this.

With the arm off, you can flip that large plastic gear over, to reveal the contacts on the other side. It resembles a small LP.

Those copper fingers at the top of this photo ride along the electrical contact plates of the gear. This is how the motor knows its position, and it provides that feedback to the climate control computer. When these contacts get greasy or oily, it can't "find itself", and it the motor will keep cycling trying to find it's position. This is the clicking noise you hear.

I use electronic parts cleaner on a paper towel. Never mind the yellow lines across the photo (that's some sort of optical/lighting distortion in the camera), but the point of that is you want to scrub the "platter" on the bottom of that gear well, and also clean the copper contacts off, so they can make a clean connection. Every time I do this, I get black dust/grit/residue off the platter. I guess it's only natural -- there's some grease in the thing for the gears, so grease will eventually find its way to the platter.

Installation is the reverse of removal. Be careful to get the metal pin of the plastic arm (if yours shares this design) back into its track in the first air mix door before you attach the metal rod to the other air mix door. I've made that mistake before!