A32m2 - Charcoal Filter Flap Motor

[Lecky]

I was hoping somebody might be able to asist with a part number check?

I decided to bite the bullet and rip the dash out on my Clk to get the annoying 'snapping' sound coming from the Charcoal filter stepper motor/linkage.



This is now the 2nd time I've had to do this. About 2 years ago I had the same fault. Bought the repair kit (A2038300032) from MB and replaced the A32m2 Stepperv Motor cog (was split)that was in the kit. Also replaced the Stepper Motor at the same time. All was well for a couple of years then it started again. After ripping everything out I noticed that the cog wasn't split this time but had worn teeth - see picture below. The cog that fits into the HVAC housing and attaches to the flap appears to have a small piece of it missing (tried to highlight it in pen).



Could somebody put a part number to the cog on the right in my picture - it's the one that fits into the HVAC housing and directly attaches to the flap shaft. The repair kit mentioned earlier doesn't seem to include this part.

Sorely tempted to leave it disconnected however since I've gone this far with it I may as well do it properly. The flap moves freely by hand and I also swapped out the stepper motor again to eliminate that. Can't see what has caused this to happen apart from the plastic used to make the cog being too soft. note only one of the cogs has wear to the teeth.

Thanks in advance if anyone could check the part number for me.

 

[Codger49]

Well done for getting so intimate with your CLK, it looks absolutely frightening to me.

I have a 2006 CLK with 581 a/c, so I thought I would look at EPC for you, unfortunately I could not find any individual part resembling that particular cog. Looking around other forums didn't bring any joy either. Flap actuators only seem to be available as the footwell flap set or the kit you already have (A 203 830 00 32).

Is it possibly supplied with the 'Housing Blower Side' (A 203 830 08 03 for 581 a/c) which houses the charcoal filters? This seems to be available for around 145 Euros from MERCEDES A2038300803 Housing buy online at a good price

I would want to check further before buying though, perhaps one of the more technical members will come along and enlighten us?

 

[Lecky]

Many thanks for the reply and research you did Codger49, most helpful. I did wonder if the cog may be part of the housing. Replacing that might just be a step too far though as it involves a lot more disconnecting.

Out of desperation I contacted my local dealer who was unable to identify the part. Reading posts on other forums gives me the impression that the broken part of the RH cog in my picture was there to hit a stop on the housing. Not too sure how the stepper is designed to stop at its limits i.e does it sense an increase in current or is there some king of angular measurement stored in the memory? dont know.

Will be messing about with it some more later on today.

 

[Lecky]

Well, I've had a few more hours on the car today. Removed the blower motor and charcoal filters. The flap is moving freely with no binding at all. refitted the cogs and stepper motor. Observed the cogs through the air inletfrom the engine bay. Interesting that when the ignition is switched off everything goes into s shut down mode. The last motor to be moving is the a32m2 - this from memory has always been the case. Take key out and it stops immediately. So playing around with it I noted that during this shut down phase the motor is still driving even though the flap is hard up against the stop. The cog attached to the motor is jumping due to the worn teeth and causing the snapping sound.

I then removed the motor and watched it during the shut down phase. Basically it motors one way for a while then the other. It kept doing this for about a minute before stopping. I tried it again but this time applied resistance to the motor shaft. Motor stops when a little resistance is felt. I repeated this a few times in both directions with the same results. So to conclude, the motors do stop when they experience a little resistance - increased current. basically it looks like the cogs MB use are not really up to the job. Will go back to MB next week to try and identify the cog that doesn't appear to come with the repair kit - unless anyone on here can?

Cheers.