I know this is a long shot but I plan to tackle the stepper motor arm replacement once the outside temps warm up a bit. My 2005 C240 Wagon had the HVAC stepper motor arm break which I know is a PIA to get to.

I have read through the sticky on this subject and downloaded the various helpful DIY documents in there, so feel moderately prepared. But was hoping someone with experience in the area would be willing to chat with me about the process. Even if not in the area that would be okay too!

Thanks!

 

Last year I installed a Command GPS, and spent countless hours assembling and reassembling the dash. There are several tutorials with pics that are useful, but I'm also glad to help. I haven't done the stepper motor, but from what I have read it sure sounds like a pain. The hardest part about is not breaking anything, especially on the vent!!

 

Thanks, Lex! I'll PM you. If you have a few minutes for me to pick your brain over the phone at some point that would be awesome. I'll owe you!

 

ehh.. what Lex has done is peanuts compared to what you are facing... Good luck!

 

Thanks for saying my hard work was peanuts. Have you taken apart the dash of the w203 or just read about it?

I'd be fearful of doing the stepper motor as well. However, if you have the time it seems doable. The dash will be in pieces which I find disconcerting. If you fail you can just put her back together and no harm done- as opposed to other repairs or mods where it is easy to damage vital engine components ..

 

VVF have you done it this job? I plan to use the attached instructions for the job (pulled down from the sticky on this subject RE: stepper motors) which are pretty thorough. I was just looking for someone with knowledge of what is involved in case I get stuck. Thankfully we are a three vehicle family so I plan to hold off on doing this until spring when I can drive my Miata daily without fear of snow.

 

Which motors do you have to replace? I removed the compete dash, steering wheel, IC, glove box and all of the central console.
While it did take forever none of it is really hard. If you have any questions I can try to remember but its been a few years.

 

I have read that there are better aftermarket machined arms available - you may want to seek that out. I also read that this is to be a pre-face lift issue, so I am shocked to see your MY2005 affected. What is your build date?

I would take this opportunity to add anything you wanted to do (PTS display, NAV, smog/multi-function sensor (Climatronic) etc. Why not?)

Moreover - it looks like time. As previously posted, not hard - just time. Please ensure you have a good quality set of SOFT tools (no marring plastic trim tools) and poly/zip lock bags and a Sharpie to label the hardware to part.

When in doubt, and I don't know your skill set or confidence level, but you plan to tackle it - so you will...just use low tack/painters masking tape (or tape rags/cloths) to protect things while you work. Even WIS shows this in various procedures, removing the headliner comes to mind - there are very specific areas MB states to cover when working and removing.

Watch this;

 

Thanks for the response. I would say I am an advanced DIYourselfer. I have been working on my own cars since about 2007 and have done everything from basic oil changes, to transmission services, rear main seals, water pumps, pulleys, belts, steering wheels, window regulators, even changed a transfer case on my Suburban.

The instructions provided on the W203 sticky (which I read through the full 28 pages of the thread) are awesome. However, I have found it can be extremely helpful once you have everything apart to have someone knowledgable you can reach out to if you are stuck.

Good call on the soft tools - I have had a few of those over the years but probably need some new ones. Yeah I probably won't tackle this job until early Spring when it warm enough I can work on it on my driveway at night without freezing my butt off and can just leave it half taken apart. I imagine it will take multiple days (doubt I will do it straight through). I don't think removing the headliner is part of the procedure - at least I hope not!

 

Yup that's about what I expected. I am thinking about replacing my steering wheel and my multi-function switch (wipers, etc.) while I am at it since my wipers have been acting funky.

In the diagram below (C240) I need to replace the M2/16 (top left corner) which is up kind of high unfortunately.



Mercedes actually has a new part number for these linkages that is beefier plastic that shouldn't brake. At least I don't have a C320 that actually has TWO stepper motors for the defrost.

 

I have replaced the evaporator core (like in video above) and what a nightmare it was. I was foolish for not replacing all of the links with the revised stronger ones while the dash was taken apart.

Dont make the same mistake, just replace all of them while you are at it. I had to take dash apart again ~2 years later when the links started to go

Factory instructions can be provided in case you want them

 

Not sure if those instructions are sufficient. I had to rip apart the dash a few years ago to replace a stepper motor. For me it was the M2/15, which was accessible without having to physically remove the HVAC air box assembly. M2/16 looks way nastier to get to.

It took me about 4h to open up the dash and another 4h to put everything back after the repair. As others have mentioned, change out all those linkages if they haven't already been replaced. This is a job you definitely do not want to do twice. The good news is that the car is still driveable (just be careful with the parking brake cable), even when everything is ripped apart. I spread the repair over several days. In terms of the sheer number of parts requiring removal, I think this job is only topped by the (similar) evaporator core job shown in that video. Yes, repairing a door lock module is less painful than this repair.

As for my 2 cents - document and group (use a bunch of numbered small bowls) the fasteners as you undo them. You'll be undoing 30+ (probably way more if you have to remove the airbox) screws, in 10 or so "groups". Many of them look similar, but will be different (slightly different lengths, some have washers etc.). This also makes it much easier to ensure you won't have to open up half the dash again because you missed one 5 steps back during re-assembly.

Also, a good professional-grade plastic pry tool is required when removing the gear shifter boot (ie the very first step). This thing is stuck in there real good. A credit card is nowhere near strong enough for this.

The other tool that is needed is a set of tamper-proof Torx, specifically that T35 for separating the centre console from the front of the dash ("page 11" of that PDF). All other fasteners were regular Torx, other than a couple of hex bolts in the centre console.