Fifth Ring

Last week, my C32 started making a "whumping" sound under the dash for the first 10 minutes after start-up. It sounds like a ventilation damper slamming shut, and it happens about every 6 seconds, and then stops after about 10 minutes or less. WHUMP.........WHUMP.......WHUMP.....

The sound reminds me of the sound one of my older cars used to make when it shut down a vent damper.

I've tried changing all the ventilation settings and it has no effect on it.

Any clues? Car goes in on Wednesday in any event.

JohnCL

What year? More than likely it is the linkage on the stepper motor.

DL_AMG

Funny! I just had the exact same problem last week. It sound like a vent flap once but with loud noise. The problem start on Friday morning and continued on every start up till Sunday night. I bring my car in last monday and I can't duplicate the problem and was like damn it...dealer won't fix unless you can duplicate it. I still have my vibration problem so I bring it in Monday and while they Reflash the Tranny and radiator (2nd time in 2 months) they found an error code regarding vent error code at left side of the car. Thank god I did mention the problem during the write up and SA told the tech to look at it and found some vent in side the heater box is out of sycn with the system. They have to take almost left side of the dash out to get to that vent unit and its a 6 hr job. Just ask dealer to see if they see any error code.

Fifth Ring

It's a 2002 C32. What's a stepper motor?

DL_AMG

I will find the invoice tonight and check the error code and parts replaced.

ScottW911

Hey, Fifth, what ever became of this problem? My car just started, this afternoon, making a sound that sounds like someone shooting a very large rubberband at the underside of the center of my dash (Whump or Thump sound). It happens every 6-10 seconds and has no bearing on the A/C being on or off.

Fifth Ring

Stepper motor. Fixed under warranty.

ScottW911

OK, knowing that the basic CPO doesn't cover non-drivetrain items, has anyone had to pay for the stepper motor and, if so, how much was it?

I don't think I can stand the sound too much longer.

Fifth Ring

No way you can live with that sound. It's like having a dying squirrel trapped in your dashboard. Gotta pay the piper.

ScottW911

Agreed. Question is: What's the Piper cost?

sales@eurocharged.com

LOL

rpayer

Mine was covered under warranty but just off the top of my head I believe the invoice was somewhere around $600.

ScottW911

Damn! When I got this car, I sold the concept of getting it to my wife based on the CPO covering repairs for a year. Then I found out the CPO does not cover this stuff and, of course, the stinkin stepper motor may end up costing me six bills!

I'm screwed, and not the way I would want to be.

rpayer

I think the invoice is in my trunk with the rest of my service records. I'll go check at lunch.

ScottW911

Well, I dropped the car at the dealer today because one of the Advisors thinks he can get it covered under warranty. Hmmm.......I sure hope so, because he did confirm it would be about $600 if it is a "customer pay" job. Stand by...

rpayer

yep... thats what mine was...$614

ScottW911

Final update for me:

I picked up my car this afternoon. The dealer did the work under warranty and cleaned and lubed the "turbo clutch" to eliminate a whining sound I was hearing while accelcerating. I am assuming they meant the S/C clutch.

Anyway, my dealer doesn't show pricing for warranty work so I am guessing from earlier conversations that it would hav been over $600 to repair the stepper motor. I was surprised how extensive a job it is to repair that motor.

Fifth Ring

Lubed the turbo clutch? Did they change the blinker fluid too?

ScottW911

Holy Crap!! That's funny!

ScottW911

Damn!

I'm driving my C32, this morning, for about 5 minutes when, Thump!.....Thump! from the right side of the dash. I immediately recognize the sound as the POS stepper motor linkage.

When I had this replaced at the end of '06, I thought I had been told that MB was replacing the crappy $.25 piece of plastic with an improved design. NOT!

So, now I am dealing with the ongoing pogo door lock, the creaking front bushings and, now, the thumping dashboard.

All in all, about $1800-$2000 in repairs by my estimate.

Today, I hate my car. Updates to follow.

testknight

There is a DIY on how to fix this somewhere. I have the same issue and it doesn't seem to hurt me other than being mildly annoying the first few minutes after starting the car. I just know when I researched this in the past I did find that someone did awrite up on repair. In my head I remember it being cheap but time consuming.

ScottW911

Actually, I forwarded that DIY to a friend of mine a couple of years ago. She had her mechanically-inclined boyfriend spend a weekend tearing her dash apart before putting it back together, without fixing it. She had ordered the entire stepper motor kit pretty cheap. She ended up taking it to an independent to do the work. What a PITA.

I might be able to live with the sound, except when the airflow in directed to the wrong vents. I hate it when my A/C is blowing on my feet and not in my face.

That is the same reason I still have the pogo lock. The part is cheap. The labor is intensive.

southernwake

Mine did this about 2 weeks after I bought it. It has since stopped, did it for about 4-5 days. I figured it was a vent door having issues opening.
I searched and could not find the DIY that was mentioned.

I have also noticed that when my A/C is on high or at least on 3/4 power or higher that you can hear the air surge, it blows cold constantly but you can hear the air blow hard for a second then go back to normal. It does this every 15-20 seconds. Not sure if this is an side effect of the stepper motor or not.

Also found out my car's A/C gets weak on a long road trip. Seems that after 2 hours it starts to die in terms of power. I can have the A/C on full and can barely feel it from the front vents(still ice cold) but from the rear vents it is blowing hard. Could this be a side effect of the stepper motor as well or am I looking in the wrong direction for this issue?

Andrew

sweet jones

having the same problem along with the so called pogo door lock situation. all on the passengers side of my 04 CLK500. the diy thread would be nice.

C_DirtyTwo

I had the same problem, stepper motor gone bad....PITA! And soo annoying! I had mine bad for like 2 months before I fixed it!