Hi all,
I have the same clicking noise but I'm unsure if it's the stepper or link arm. It clicks for about 100 or so, and clicks every second or two in the drivers side foot well.
I've purchased the link arms, but I'd hate to pull it all apart and find that it's the stepper.

So does anyone know if the OBD data can identify if its a stepper, and or which stepper was faulty?

And also, does anyone have a recommendation for a cheap wireless OBD2 that works with iOS.

Cheers

matt

 

The fastest way to tell which stepper it is not working is to put the system in manual, turn up the fan and switch between vent outputs to see which one is not opening/closing. In my case it was the defrost that was not opening and there was no linkage on that one, just a direct motor to shaft connection. If you do tear it apart and find a bad stepper, you can swap it for a working one in an easy to replace position (like the recirculating flapper) until you can get a new one.

 

Had the described problems for a few years. Clicked and clacked for the first minute or two after start and then went away. Now it doesn't do it at all and all the modes seem to work fine. My ignorance saved a ton of money. Now if only someone could help me with the saggy headliner.

 

My problem is different than broken linkage. My car's problem is broken gears in stepper motor.
In addition, this message can help you:
https://mbworld.org/forums/5977229-post44.html

 

I had that problem last week and I was very worry because that was horrible.
After search some web site and call the dealer I realize that's so expensive to fix ($900 NZD)
After a week I discovered we can remove fuse number 30 from cockpit box,that's doesn't any error in KM monitor just air condition fan doesn't work and noise off!
Another surprise is when I put fuse(number 30) turn back to fuse box, stepper plastic link move and break.
Now no any noise from dashboard any more. lol

 

I've finally managed to grow the pair necessary to jump in and fix the hella noisy AC stepper motors and links on my lovely 01 C320. But before I jump in and tackle this massive project, I have a few questions for you guys.

1) Are all stepper motors interchangeable? Can the same motor (with different linkages) work for say M2/19 and M2/6?

2) I've played around with the manual controls on the AC vents and I've narrowed the problem as follows:

M2/9, linkages are 90% bad. It has a very quiet click and right defrost doesn't work. So that's easy...

....but the question is now M2/19 vs M2/6. The left front vents kinda blow the same pressure and temperature (room temp) air regardless of the direction I set it at. In the winter, air coming out of the left vents was cold, regardless of temperature, but all other vents like left feet or right front vents blew air at the expected temperature. What do you guys think? Could be both....

3) Since this thread (like on page 10) suggests that a broken motor has the loud snapping noise that can start and stop when driving and I have a loud snapping noise that stops and NEVER EVER starts again after 1 minute or so as it is common with broken linkages, I'm posting a video with the sound. So motor(s) or linkage(s)?
4) Just some housekeeping on ordering the right parts, for the linkages, is this the only thing I need to order and that covers all the linkages for all motors (like M2/9 and M2/19 or M2/6)? http://www.rmeuropean.com/Part-Numbe..._5C1313F8.aspx

I know this is a long post, but I tried to make it as clear as possible to make this smooth. Thanks you all!

 

Yes, all the same.


My experience is it usually turns out to be something other than what you think it is. Foot well vents (both sides) are most common. Passenger side defrost requires removing upper dash to access. Driver's side defrost works well enough for both sides.

Odd that it keeps going after you shut down. Sounds like a louder than usual linkage though. Hard to tell. Take it apart so you can see everything, turn key to first position BUT NOT BEYOND, plug in control unit, put it in test mode and watch/listen. If any of the motors or linkages fail the test will never stop.....so be aware that if the defrost is broken even after you fix everything else the test won't pass. If the passenger defrost is failing/making a noise you can get a looong screwdriver and something to unlatch the motor to disconnect it to stop the noise. You can disconnect motors one at a time to narrow things down.

Yes, last time I ordered them a couple of years ago. Replace as many as you can while you're in there! Good luck!

 

I went ahead and did it, spent all of today on it as I had a day off from work. Let me just say how thankful I am for the information in this thread and the PDFs everyone posted -- without them I would have totally screwed. Thanks!

That loud noise I posted in the video was M2/19 with a broken motor. I replaced the motor and its appropriate gear. Now I have a bunch of gears and links that I have no use for. If you are in the Northern Virginia/ DC area and want some, let me know, I will give you the rest of the set for something like $10 bucks. If you are farther away, same deal + you pay for shipping.

While things went relatively smoothly, I have two issues. The "easy" one is that I can't particularly figure out how to put back the center vents with the trim. This is how I have it now: http://imageshack.com/a/img834/2847/m45w.jpg -- I don't think it's all the way in either, but i can't figure out how to do it. The trim part came off when I was pulling it out and some of its latches are broken, but I didn't think it would prevent putting it back in. Not meaning to go too offtopic, but does any W203 center vents fit with all model years? Found some on eBay, but they are listed as 2003+....

The more serious issue is that the radio is gone. I made a mistake when plugging things back in as i forgot to connect the CD-changer connector and it turned on and told me there was no CD changer. I shut it off, unplugged everything and realized that i was missing the CD changer cord. Plugged everything back in and now the head unit doesn't turn on and the CD changer has no power as well. I changed the fuse on the back of the radio and it wasn't it. I will change the one in the engine compartment and I'm keeping my fingers crossed.

So yeah, this is not for the faint hearted......

 

Seems my stepper motors last only 240k miles Hooked my car to Star and found M2/15 and M2/21 motors to be dead.

For my amusement I asked a quote from dealer and it was $800 for labor and $585 for parts (motors $280 each).

A bit jealous for you US guys there, I can find brand new motors for less than $80 but it seems to be impossible to find below $200 from Europe. If anyone knows good websites for these parts in Europe, please tell me aswell. I can not order from US because I need to pay ridiculous import taxes.

Edit:

I asked many quotes from around the Europe and the cheapest original motors I've found from a german authorized M-B service/part shop called http://www.baldshop.de/ at price of 127e ~$175. They dont have them listed on the website, so write email to them instead with part number and they can send a bill directly to your PayPal account and ship it to you. Excellent and fast service. On the other side of the scale, one british shop quoted me for 205 pounds ~ $345 for the same part...

 

I am in Ft Worth and can bring the car to you. What would be worst case charges? 2001 C320 with Command

 

I would like to thank those who made up this article and cut to the chase. lots of questions on the net beat around the bush but this one went to the heart with detailed description and detailed photos. The clicking noise in my dash has driven me mad and i am certain my merc mechanic would charge the day or more to fix it, $600-$1200 i would estimate. I dare not ask him for a quote.

I havn't started the job but would be interested in giving it a go. Oh boy though, it certainly looks scary tearing all that tight fitting dash apart and would hate to get stuck half way and chicken out!!!

Stepper motors finally appear very tricky to get to even when every thing is stripped away.

Wonderful job to all involved in the article.

Cheers Malcolm Australia.

 

In my 03 C230 the air is not coming out of face nor side vents, everything else is fine. It happened gradually during a year or so. First it would take a minute than 10 minutes for the air to come out and now the air is not blowing at all. I don't hear any clicking or other noise. Which motor or linkage could it be? Would I have to remove center console and underdash to access/fix it? Can somebody please advise?

 

This image maybe help you.
https://mbworld.org/forums/attachmen...8340342300.jpg

 

My turn to have this issue. Again. A big thanks to Racin_fool, liveniceguy, Wilsophia, and krazzdav! The PDFs were super useful when ripping apart my car.

1st time was covered by warranty, and was caused by the weak (undersized) arms. They mentioned something in the invoice about replacing motor M2/15 (L footwell) but guess they didn't, as this is the one that failed on me this time (the 2nd time).

Took me 5h to open up the dash. The instructions were pretty straight forward. I got stuck at 1 part - the "turn the T35 screw 90 degrees" bit. I had turned them both a bit too far, passing the "sweet spot" where the centre console will disengage from the lower dash pieces. If I were to do it again, I would turn the screws by hand, all the while jiggling the centre console - gently pulling the whole assembly towards the back of the car.

The other tip - make sure you have a good pry tool. That gear shifter boot (very first step) is ridiculously tight.

The 1st time (broken linkage), the noise was a VERY loud snap - it sounded like someone fracturing a brittle piece of plastic. The 2nd time, it was more like a "thump thump thump", 1s apart. After reading the thread, I assumed it was another broken linkage. Nope - it was a broken M2/15 motor - the gears had stripped. The others are right - do NOT buy any parts until you are SURE you've found the problem! It took me a while to solve the problem too, as only certain teeth were damaged, so the thumping was intermittent. Notice the black marks on certain teeth.

Servo motor part # is A203-820-16-42.

To give you an idea of how much money one can save by DIYing this, I sourced the servo motor for $79USD, including shipping and no tax (RM European). The pry tool set and Torx bits were another $60, for a total of $139. Just for fun, I called the dealer for a quote to replace that exact servo. 7h labour ($940), and $284 for the motor. Add 12% tax (British Columbia), and it's now $1371.

Anyone know if a a car be easily converted "partially" for dual zone? Wondering if I can simply buy a linkage kit and 2 more motors and install M2/20 and M2/11, for dual zone footwell control. I couldn't see any more servo motor connectors, but didn't check the full length of the cable. I've done the Climatronic mod, which allows for 2 zones.

 

New here and glad to see the exploded views . 2004 C320 Sport Sedan ...Mine is working on the pass side However the drivers side is blowing on the floor and at you..WHen you call for it 100% directly at you.. It will go into defrost mode. As well when I hit the recirc button that does not seem to work. In most vehicles the noise of the fan will increase.. First Mercedes , had BMW before this and not many heat cool issues but did get very good with oil leaks and double vanos repairs on mine and friends .

 

BTW, for those of you with coupe or C240 with single zone (ie button only HVAC switch control / non-digital Climatronic from factory) - don't look for that right side footwell stepper motor and actuator linkage, the car doesn't have it! I spent an hour looking for something that doesn't even exist. Fustrating and embarrassing! I least when I look for a part that doesn't even exist on a woman, it's fun!

I'm with Slammer111, I also have done HVAC digital Climatronic mod and investigated adding real dual zone to my coupe. Never done it but given it some serious thought. Yes, you'll need the linkage kit,... and any flaps they connect to! Problem is you're only adding 2 more stepper motor for partial dual - should be 4 for fully dual zone since our coupe and C240 with single zone only has 6 stepper motor and fully loaded dual zone cars has 10 stepper motors. But the real pain is changing the wiring, the wires are connected in series so you will have to be able to access every single stepper motor which means tearing apart the entire dash. And then you'll have to code it on MB STAR Diagnostic System. End of the day, better to just buy an entire under dash HVAC system and switch out your existing one then code on MB STAR. Either way, I don't think it's worth it. I'm happy just to be a digital Climatronic dual zone Poser!

Removing the radio centre console cage was a real pain,... literally, I almost dislocated my shoulder! It's not just the two tabs in the back (attached to steel supports) that everyone is talking about that's difficult,.. but plastic nipple at the front! This radio centre console black plastic cage is suspended in place like a vise! The 2 tabs in the back attached to steel supports hidden by foam but it's the front part that's hidden just behind the dash under the centre air vent that you must tackle! That dash piece look weak but it's reinforced in the back with little shelves to hold the the radio centre console black plastic cage in place (see image in mirror in first photo). In the middle of that dash piece there's a screw and to the right of that a little plastic nipple that locks the radio centre console cage dead centre. DRILL OUT this plastic nipple! Then it'll allow the radio centre console cage to wiggle from side to side and there's enough flex to just pull it down. You still need to deal with the two tabs in the back but now it's a lot easier. When re-installing, the plastic nipple was drilled out with 1/4",... so when re-installing put in a (rather low profile flat head) bolt and nut.

 

About to do this to my 02 c240 which is clicking and hissing. Can someone clarify that the part I need is the one linked below?
https://importecautoparts.com/parts/part_number/203%20830%2000%2032/3

 

I would recommend diagnosing what is actually the problem first. It will be a pain in the butt taking everything apart 2x or just leaving it apart but it could just be a stepper motor and not the linkages, just the motor or both. For mine it was a stepper motor, a couple of the levers the stepper motor connected to as well as the footwell levers.

The kit you listed is correct for the stepper motor controls (A2038300032) but then you may also need PN# A2038300033 (footwell linkages which I would change anyways--they are stronger than the original ones) and stepper motor A2038201642

The hissing sound is not related to the clicking sound--that is an indication that your AC system is low on freon. You will need to evac your system, put UV dye so you can check for leaks and recharge it. I just found that you can not charge it from the kits you can buy at the stores by pressure but has to be charged by weight.

 

The PDF in this thread is really helpful getting the console and lower dash out to get to the stepper motors. The part at the very end about how to remove the upper dash to get to the remaining stepper motors didn't help me though. They instruct that you remove the wipers to get to a bolt holding the frame. I did not need to do this to access the defroster stepper motors. I only needed to remove the dash cover, not the frame. I have a print-out of the instructions of how to remove the dash cover if anyone needs it. This is for a 2001 W203 Mercedes C320.

 

I guess it's my cars turn. My 01 C320 randomly started doing a "click-thunk" noise from behind the dash that goes away after about 20-30 seconds of turning on the car. All vents work, AC is fine, heat is fine, air flow is normal (questionably weak when it comes to the windshield vent, not sure if the air flow is normal for the model, but it works regardless.) Aside from that initial 30 seconds, all else is well, so I'm inclined to just ignore it since it's not a persistent noise. I'm just trying to see if it may be related to the stepper motor, or if it's something else.

 

Mine was the exact same and was one stepper motor and I think 3 of the plastic arms/levers/wheels that were broken. If u don't mind leaving ur dash apart it's recommended to c what's wrong first then buy those parts. If not I recommend buying all the plastic pieces only. If it is a stepper motor that's bad move it to a spot that's easy to get to then buy it. This way you only have to take part of the dash apart by the radio.

 

You can test the stepper motors by pressing the left defrost and recirculate buttons simultaneously and hold for 10 seconds until both lights flash off and on. If they go off after about 30 seconds, the motors are OK. If not, you have a problem with one or more of the motors.

 

This is not entirely true as it could just be one of the linkages for the motor

 

Yes, or, it could be a faulty vent flap, obstruction, or any other malfunction that would require removal of the motor to diagnose.

 

I've just decided to ignore it for now. The 6 clicks it does at startup (yes, I've counted) don't annoy me enough to pay over a thousand dollars to fix. Going to try pulling fuse 30 to see what happens.