C-Class (W203) 2001-2007, C160, C180, C200, C220, C230, C240, C270, C280, C300, C320, C230K, C350, Coupe

Noisy Air Conditioner ?? Stepper Motor Replacement / Clicking & Hissing

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Old Apr 16, 2015 | 12:55 AM
  #526  
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W203 '05 C240 4matic
Last question, I noticed while reading the directions that the pics are of a pre-face lift model. Do the same directions apply to the face lift models aswell? Because my center counsol and arm rest are a little different. thanks!
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Old Apr 27, 2015 | 11:44 AM
  #527  
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cvx
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W203 C200CDI
Originally Posted by cvx
Decided to ask here before starting a new thread.

Any idea what is the hissing sound coming from the center vents? Here is a video of the same sound from some BMW driver: (Cant give own video yet)

E46 A/C Hissing Sound - YouTube

My stepper motors are fine and also tried another blower. Core evaporator changed 2 years ago. The AC worked last summer, but could it still need refilling? Can not test AC now since its +5 outside but the hissing sound is making me nuts. It keeps hissing no matter what temp or position the knobs are.
Bump Bump
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Old Apr 27, 2015 | 09:35 PM
  #528  
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Originally Posted by cvx
Bump Bump
cvx this is an indication your system needs recharged. You CAN NOT just buy a can from the store and add freon (not supposed to--can mess it up real bad). You have to have your entire system evacuated and refilled by total weight.
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Old May 3, 2015 | 11:13 PM
  #529  
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W203 '05 C240 4matic
Done, I think....

Whats up everybody. I just finished up replacing the m2/15 stepper motor for my c240. It literally took me all day. The directions that the other members wrote were very good. I didnt have the black radio cage that everyone had a hard time taking off, I had a white one that took me 5 minutes to remove. I just located the 2 tabs that hold it in place and hammered them through with a flat head screwdriver. Everything went kinda smooth. Wasn't hard just a little annoying.

Now here's my dilemma...... The plastic lever arm was good. I didnt have to replace it since it was the upgraded version. But the stepper motor was shot. I took it apart and saw that some of the teeth on the gear were gone. I replaced the motor and when I plugged it all back in and go to resync the motor doesnt move. All the other motors move around. I pushed it a little and it doesnt budge. And after about 30 seconds the a/c control stops resyncing. I still get a little air on the footwell but not like before. So I dont know if its working or not? What do you guys think? Should I go back in there and replace the motor or do something else or go to my mechanic and ask him to hook it up to his computer?

Thanks everyone!

Last edited by Benzomatic76; May 3, 2015 at 11:15 PM.
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Old May 3, 2015 | 11:30 PM
  #530  
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Originally Posted by Benzomatic76
.. So I dont know if its working or not? ...
Put it in a location/flap that works to see if the motor is OK. You may have a bad replacement motor.
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Old May 3, 2015 | 11:45 PM
  #531  
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W203 '05 C240 4matic
Hey thanks man for the quick reply! I tried all the settings and it still doesnt move. I think you're right I might have a bad motor. But if that were the case why would the resyncing process stop?

I forgot to mention, that brace that the motor hids behind is a royal PITA!! Its so hard to move the motor around. If I have to get in there again I just might sawzall that brace out and then just reattach it with some metal brackets and self drilling screws.
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Old May 3, 2015 | 11:57 PM
  #532  
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Originally Posted by Benzomatic76
...I tried all the settings and it still doesnt move. I think you're right I might have a bad motor. But if that were the case why would the resyncing process stop?....
The resync stops because it doesn't get the feedback from the motor working correctly. If it continually cycles and doesn't stop (broken plastic arm) or never moves (bad motor or connector or) then the sync continues forever. Just put the motor into a known good location and see if it works.

Originally Posted by Benzomatic76
...I forgot to mention, that brace that the motor hids behind is a royal PITA!! Its so hard to move the motor around. If I have to get in there again I just might sawzall that brace out and then just reattach it with some metal brackets and self drilling screws.
The AC system is all plastic. Don' be afraid to move/bend things to get better access to connectors.
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Old May 4, 2015 | 06:33 AM
  #533  
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I have a 2005 c240... Will these instructions posted to replace stepper motor linkage be the same for an 05 C240? I noticed the years covered stops at 2004, thx
Ant
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Old May 4, 2015 | 06:58 AM
  #534  
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W203 '05 C240 4matic
Originally Posted by awbooth
I have a 2005 c240... Will these instructions posted to replace stepper motor linkage be the same for an 05 C240? I noticed the years covered stops at 2004, thx
Ant
Yes pretty much. I have a 05 c240.
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Old May 4, 2015 | 07:00 AM
  #535  
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W203 '05 C240 4matic
Originally Posted by mleskovar
The resync stops because it doesn't get the feedback from the motor working correctly. If it continually cycles and doesn't stop (broken plastic arm) or never moves (bad motor or connector or) then the sync continues forever. Just put the motor into a known good location and see if it works.



The AC system is all plastic. Don' be afraid to move/bend things to get better access to connectors.
Thanks man for your help. I cant do anything today. I have to wait until next sunday to takle it again. But on the bright side no more annoying clicking!
Thanks!
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Old May 4, 2015 | 08:20 AM
  #536  
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2013 Mercedes benz ML350 4Matic
I HAVE A 2005 C240 4MATIC. IS THE STEPPER MOTOR LINKAGE ARM part number #A203-830-00-33? THANKS
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Old May 4, 2015 | 07:07 PM
  #537  
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W203 '05 C240 4matic
Originally Posted by awbooth
I HAVE A 2005 C240 4MATIC. IS THE STEPPER MOTOR LINKAGE ARM part number #A203-830-00-33? THANKS
Yes it is. But you might also need the stepper motor too. I bought all the linkage arms only to find out my motor was bad. But here is the link to the linkage arms.
http://www.ecstuning.com/Mercedes_Benz-2005-C240-203.081-4Matic-Sedan-V6_2.6L_112.916/Search/SiteSearch/2038300033/
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Old May 4, 2015 | 08:41 PM
  #538  
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Originally Posted by Benzomatic76
Yes it is. But you might also need the stepper motor too. I bought all the linkage arms only to find out my motor was bad. But here is the link to the linkage arms.
http://www.ecstuning.com/Mercedes_Benz-2005-C240-203.081-4Matic-Sedan-V6_2.6L_112.916/Search/SiteSearch/2038300033/
Thank you!! Appreciate ur help
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Old May 5, 2015 | 01:28 PM
  #539  
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Originally Posted by Benzomatic76
Yes it is. But you might also need the stepper motor too. I bought all the linkage arms only to find out my motor was bad. But here is the link to the linkage arms.
http://www.ecstuning.com/Mercedes_Be...ch/2038300033/
Benzomatic76,

Thank you for posting a link to our site!

David
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Old May 7, 2015 | 12:47 AM
  #540  
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W203 '05 C240 4matic
Originally Posted by ECSTuning
Benzomatic76,

Thank you for posting a link to our site!

David
Hey no problem. I always order from you guys!
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Old May 8, 2015 | 08:35 PM
  #541  
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2013 Mercedes benz ML350 4Matic
replacing oem radio in c240, will the steering wheel buttons still work on new radio.

I'm replacing the OEM radio in my 2005 c240 4 matic. I was curious if the steering wheel controls for the radio will still work? Such as volume, changing the radio stations, etc? Thanks
Ant
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Old May 19, 2015 | 10:57 PM
  #542  
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2005 C240 Wagon
This thread is full of great info - kudos to all who've contributed and those who have accepted the challenge of tearing the car apart!

I have an odd noise that may or may not be related to the steppers and arms. The car is a 2005 C240 4matic Wagon, post facelift. When I sync the steppers I feel air everywhere it is supposed to be (although it seems to take a long time to switch from dash front to dash top, normal?).

The noise I have is a little tic tic tic that is constant when the blower motor is between 2 and 3.5. It also makes the noise when in auto mode and the fan is blowing at a low speed. Under braking the noise goes away, under acceleration it gets a little louder. It does not eem to change speed with the blower fan and it does not stop after 3,4 or 8 minutes - it will do it all day. It is a light tic, not a loud snap.

I pulled the cabin air filter out (under the hood) and ran the fan at all speeds but couldn't hear any noise there. It seems to me it might be related to a flapper door since it changes with the attitude of the car but since it passes the sync test - and all the air goes where it is supposed to go - I can't imagine it's a broken linkage.

I'm thinking I'll pull the motor out and see if there is anything in there, debris or something, that could be getting into the fan. Anyone else have thoughts? Seen it?

Thanks,
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Old May 19, 2015 | 11:20 PM
  #543  
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Originally Posted by RadDad
...Under braking the noise goes away, under acceleration it gets a little louder. ..Thanks,
It is most likely your blower motor/fan. The bearing has seen its' better days.
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Old May 20, 2015 | 09:59 PM
  #544  
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2005 C240 Wagon
Originally Posted by mleskovar
It is most likely your blower motor/fan. The bearing has seen its' better days.
Thanks!

I'll give it a more thorough listen this weekend from inside and out. Doesn't look too hard to remove and install.
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Old May 22, 2015 | 11:26 AM
  #545  
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Found ticking from the motors closest to the steering wheel and behind the radio. I got lucky - both now fixed without any new parts!

Firstly let me say thanks for the great instructions on how to find these.

Job #1:

This one next to the steering wheel (UK RHD car) didn't have a broken arm, the motor itself was ticking:


So opening up the motor:


... revealed a few teeth on the white gear had worn away.


This particular vent flap only requires a very small travel to do its job (stepper moves through about 1/3 of a complete circle), so removing and rotating the white gear such that the worn-out part sits at the other side fixes the problem!

This short range of movement is specific to the vent flap previously pictured. Others move a lot further, but you could try it out anyway.

Reassembly. The larger black and white gears seen before stay in place (note the worn side of the white gear is now at the opposite end). Add the spring under where the smallest white gear is shown, then pushing down on the smallest gear add the remaining white gear on top. There's a few pins in the lid you need to line up, the most fiddly being the one that centres the smallest gear:


So now your motor is back in one piece with the worn-out section away from contact, set it up on the car with the vent in its half-open position. This ensures those broken teeth never come back into contact with the rest of the mech.


Give it a go - it worked for me!!!

Job #2:

So the other problem sat behind the radio. It was ticking but neither the external nor the internal gears were damaged - odd!


It turns out the external gears had previously skipped one tooth, meaning the specific large-tooth and associated notch were no longer aligned.

I didn't get any pics of this, so in more detail: the car-side gear has one tooth larger than the rest. On the motor-side gear there's an associated cut-out to accommodate this large tooth. If the mech isn't lined up then the large tooth is forced to roll over a non-notched section, forcing everything to flex and resulting in a 'thump' as the highest part of the tooth is cleared.

Remove the motor and realign the large-tooth and notch to cure the issue.

Remember to re-sync with the Recirc+Defrost combo!


Last edited by albad; May 22, 2015 at 11:36 AM.
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Old May 24, 2015 | 02:37 PM
  #546  
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Originally Posted by albad
Found ticking from the motors closest to the steering wheel and behind the radio. I got lucky - both now fixed without any new parts!
Good find albad! I too took my motor apart and moved the gear but on the one that was bad for me the flap traveled too much and only lasted a couple cycles so didn't think any positions would be worth noting this. Glad you found one that does work!
Strange your other vent rod and gears were misaligned....I wonder if that motor was previously changed and whoever put it in didn't align them properly.
Anyhow good looking out and making this your first post just to share with everyone!
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Old Jun 22, 2015 | 02:54 PM
  #547  
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c63 AMG
awesome, but scarey thread

Does anyone know if these stepper motor issues are common in the w204 models? Thanks
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Old Jun 23, 2015 | 02:28 AM
  #548  
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THE C350
I have never heard of this issue on the w204 but if your concerned take a quick look around on the w204 section.
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Old Jul 15, 2015 | 03:08 PM
  #549  
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2004 C240
Can someone be clear as to what T35 socket is. I suppose it is T35 torx bit because we have Exx (xx = 10, 12, etc) MM sockets and I do not know what is a T35 tox socket. Whenever this item is googled, it returns torx bits. If T35 torx bit is what I need, please can someone confirm that. Thanks everyone.
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Old Jul 16, 2015 | 12:36 AM
  #550  
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2003 C230 Sports Coupe, Paprika Metallic Red, Auto, Pano, Leather
Originally Posted by Shyone411
Can someone be clear as to what T35 socket is. I suppose it is T35 torx bit because we have Exx (xx = 10, 12, etc) MM sockets and I do not know what is a T35 tox socket. Whenever this item is googled, it returns torx bits. If T35 torx bit is what I need, please can someone confirm that. Thanks everyone.
T35 is a 6 point star shaped (torx) bit/screwdriver as oppose to -, + or square

Socket are like common hex socket
Inverted Torx socket starts with E (instead of T as in T35)

Once you figure out you need T35 shape,.... you should figure out length as in common little bit that are interchangeable or do you need longer as in on a screwdriver

Anyways, if your going to work on your Mercedes,... you should have a set of torx screwdrivers and bits,... along with set of Inverted Torx sockets,... in USA Harbor Freight has numerous sets available
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