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2000 ML 430 (W163 - A1646xx)
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4 Posts
Discussion Starter #1
Hello all. :)

...complete newbie here who is WAY IN OVER HIS HEAD!

I've had this very loud and constant knocking sound in the dash of my 2000 ML 430 (A1646xx - 143,000 miles) and so with the long weekend, I thought I'd just rip apart the entire dash and see if I could fix it (...obviously...I'm way too impulsive and also not very smart :banghead:



...anyway...now I've got a car that is in pieces and I'm wondering, if I turn the ignition to the accessories position, what will happen?

I'm sure it will throw more than a few error codes which will probably have to be cleared by a reputable shop (and I can live with that) but will anything REALLY BAD happen? For instance, is there ANY chance one or more airbags will blow if I turn the key while the car in its current state?

Maybe another way to ask this is; what is the minimum set of items I need to re-attach to the main wiring harness before I can safely re-attach the battery and turn the ignition to the accessories postion? Do I need to re-attach the instrument cluster? What about the center instrument controls or the radio/navi unit? How about the passenger air bag?

...thanks in advance, for any help you can offer this complete knucklehead.

--Steve
 

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Premium Member
2000 ML55 sold? 2013 ML500,? 2015 C250 estate wagon, 1927 Dodge 4 sedan, 1929 Dodge
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4,926 Posts
personaly, i would have disconnnected the battery way before that stage.It dosn't look like much would work if you did turn the key to acc. but i wouldn't. Good luck with all that i hope you find that noise and get it back together.....
 

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2004 CLK 240 Coupe
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11,377 Posts
Maybe another way to ask this is; what is the minimum set of items I need to re-attach to the main wiring harness before I can safely re-attach the battery and turn the ignition to the accessories postion?
I expect a number of us are wondering - why would you want to do that anyway? Are you missing your radio?
 

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2000 ML 430 (W163 - A1646xx)
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4 Posts
Discussion Starter #4
Hi Matt and thanks for the reply. :)

In my original post, I didn't really get into all the steps I followed to get to this point, but I did begin this whole "adventure" by disconnecting the battery as step one.

Now that I can get a better look into the dash, I simply need a way to SAFELY power-up the system again so I can recreate the original sound.

As many other members have reported with a faulty blend air door actuator motor, when I initially took the ML to the dealership to have the knocking sound diagnosed, they told me that it was likely some actuator motor in the climate control system. They said there are something like 6 possible motors in that system that could be broken and causing the noise but they would have to completely dismantle the dash to find which one needed to be replaced (about 8-10 hours of labor).

Now that I have dismantled the dash, I simply want to know if there is a way to safely power-up the system to try to isolate the noisy/faulty component...much as I imagine the mechanics at the dealership would do at this point.

...anyone else have some advice for me at this point?

Thanks.
--Steve
 

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ML320 2002
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1,602 Posts
I drove the car without instrument cluster and radio. No problem here. I wouldn't worry about the instrument panel controls. But system will turn on SRS airbag light because it will not detect front airbag. Will the SRS light go off whem everything put in place? If you tampered with the airbag, it will take you to the dealer/mechanic.

Maybe you should describe your problem now. If you are lucky, someone else had the same problem and will help you.
 

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2000 ML 430 (W163 - A1646xx)
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4 Posts
Discussion Starter #6
Thank you very much, Merzatt for your reply! ...that is very good to know. :)

I'm sure I have a bad blend air door actuator motor as many other members have excellently documented (props to DETANE and 43sqd et al :)
I've removed and disassembled that part and I can see that the cheapo plastic gears in that motor are broken and cracked in several places.

If I were smarter (which this project has conclusively shown I am not), I would have started by just replacing this one part according to DETANE's excellent video DIY and then seen if that was the one source for the knocking sound.

As it is though, now that I have the dash completely torn-apart, I figure I might as well take the time to make sure there is nothing else broken in there.

The thing that has really thrown me off here, is that my original noise was not a mild clicking or ticking sound. It was a very loud rhythmic knocking sound. It would start-up as soon as the key was put into the accessory position or when the ignition was turned all the way over, and would continue no matter what I did with any of the various climate controls (fans on, full-bast, or off / temperature hot or cold / AC on, full-blast, or off / vents set to upper dash, console vents or foot wells).

Also, despite the fact that the gears in the blend air door actuator motor appear to be in really bad shape, all the climate controls seemed to work OK (I was able to get hot or cold air out of the system and redirect the air to whatever set of vents I wanted).

...I would have just left well-enough alone, except, that ef'n knocking sound was driving me crazy! :mad:
Even with music turned-up to a reasonably loud level, I could still hear that knocking sounds coming through; like a drum beat that was out-of-sync with whatever song happened to be playing.

...anyway...so here I am.

Thanks a ton for letting me know that you have personally driven your ML with a partially dismantled dash. I don't plan to do the same (only need to test the system) but it is nice to know I have the option if it gets to the point that I want to drive it somewhere to have a professional clean-up this major mess I have made.


THANKS!
--Steve
 

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05 500
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6,516 Posts
I drove the car without instrument cluster and radio. No problem here. ...
I'd have thought it wouldn't let you start the car with the dash disconnected. How in the world would you know what's happening? I was going to fix my 01 E's dash and that same Q came up. The info I got from the W210 forum was that the system will not let you start the car with the dash out. It's interesting that you were able to d
rive the truck without dash connected!
 

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ML320 2002
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I'd have thought it wouldn't let you start the car with the dash disconnected. How in the world would you know what's happening? I was going to fix my 01 E's dash and that same Q came up. The info I got from the W210 forum was that the system will not let you start the car with the dash out. It's interesting that you were able to d
rive the truck without dash connected!
Yes, it happened. But didn't remove the entire dashboard. I drove the car without the instrument cluster to the parts store so I could get a tool to finish the job. I was fixing the clicking sound coming from the central air duct actuator. The easiest way to reach that thing is from the instrument cluster hole. Nothing happened other than the time on the clock was reset.
 

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2000 ML430 SOLD, 2007 BMW 328i Coupe, 2014 BMW i3, 2019 Honda Odyssey
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Oh my goodness, I've started tearing trim pieces apart before, but nothing like this! That said, I think your best bet would be not to try starting anything up.

Sadly, I'm also wondering if you're going to have more squeaks and rattles now... Nothing ever goes back as well as it was from the factory.
 

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05 ML500 SE
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1,482 Posts
How is pulling the dash off going to make his car blow up? I would say this was a bit of an overzealous approach but I dont understand why his car would majorly malfunction. Would the worst case be that it wouldnt start? Why not plug in the instrument cluster and non hvac stuff back in? I hope you took pictures and notes.

poor humpty dumpty.

Oh Witek..... 43sqd... help this poor noise obsessed fella out. Is he gonna blow up his car if he turns it on?
 

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Dallas, Texas
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7,751 Posts
Hi Matt and thanks for the reply. :)

In my original post, I didn't really get into all the steps I followed to get to this point, but I did begin this whole "adventure" by disconnecting the battery as step one.

Now that I can get a better look into the dash, I simply need a way to SAFELY power-up the system again so I can recreate the original sound.

As many other members have reported with a faulty blend air door actuator motor, when I initially took the ML to the dealership to have the knocking sound diagnosed, they told me that it was likely some actuator motor in the climate control system. They said there are something like 6 possible motors in that system that could be broken and causing the noise but they would have to completely dismantle the dash to find which one needed to be replaced (about 8-10 hours of labor).

Now that I have dismantled the dash, I simply want to know if there is a way to safely power-up the system to try to isolate the noisy/faulty component...much as I imagine the mechanics at the dealership would do at this point.

...anyone else have some advice for me at this point?

Thanks.
--Steve
2000 model has only two servo motors. One for blending flap and one for recirculating flap. Replace them both.

Nothing will blow up when you connect battery and turn key on. With a/c controls disconnected you will not be able to recreate the noise. Servo motors run only when commanded.
 

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05 ML500 SE
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yeah might as well replace both of them... anything else he should replace while he has everything stripped off? I doubt he is going to ever want to go in there again.
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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4,714 Posts
Oh my goodness, I've started tearing trim pieces apart before, but nothing like this! That said, I think your best bet would be not to try starting anything up.

Sadly, I'm also wondering if you're going to have more squeaks and rattles now... Nothing ever goes back as well as it was from the factory.
Those were my exact thoughts also - You may well end up stopping the annoying sound you were encountering but instead also open up a Pandora's box of other more annoying sounds like rattles.

I have to say OP - You've got great big balls to dismantle your dashboard like that!:eek:

Personally, I get queasy just opening my fusebox or changing a light bulb!:D
 

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It was fun while it lasted
2002 ML320, 2005 S430 4MATIC RIP, 2010 F150 Crew Cab
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11,148 Posts
I think it looks cool all torn apart like that. Go ahead and remove the steering wheel and center console, too. It would look waaay cooler to see what it looks like, then.

All facetiousness aside, you should take several close up pics and post them here so other members may benefit from this disassembly.
 

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ML320 2002
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1,602 Posts
2000 model has only two servo motors. One for blending flap and one for recirculating flap. Replace them both.

Nothing will blow up when you connect battery and turn key on. With a/c controls disconnected you will not be able to recreate the noise. Servo motors run only when commanded.
Good point from Witek, as usual. But, you can plug in the A/C control module to it's cable and it will activate the actuator motors. Don't get discouraged by the folks here calling you crazy. Removing the dash is probably a safer method for replacing blend air door. Alternative is to do it through the glovebox hole that requires tampering with the passenger airbag module. Let's hope that replacing these will fix the noise!
 

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W163 Crash Test Driver
2008 ML350 (Me!), 2010 GLK350 (Wife), 2003 ML-350 (Deceased)
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05 ML500 SE
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Alternative is to do it through the glovebox hole that requires tampering with the passenger airbag module.
Its hardly tampering to unbolt the intact airbag unit, not actually doing anything to it.. Its the dash flap above the airbag module that has to be glued down with a couple beads of glue on the non hinging side.
 

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2002 ML320
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323 Posts
This is awesome!

Your clearly more inclined then myself, but even I replaced the air blend motor - one of the users here made a video of this project, maybe it was detane.

Either way, next time POST here first ;) then get to taking things apart!

Great stuff.
 

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Dallas, Texas
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Good point from Witek, as usual. But, you can plug in the A/C control module to it's cable and it will activate the actuator motors. Don't get discouraged by the folks here calling you crazy. Removing the dash is probably a safer method for replacing blend air door. Alternative is to do it through the glovebox hole that requires tampering with the passenger airbag module. Let's hope that replacing these will fix the noise!
Connecting just a/c controls is not gonna cut it. In car temperature sensor has to be connected as well.
 
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