203 chassis clicking under dash - PeachParts Mercedes-Benz Forum

Evan · #1 06-18-2004, 08:17 PM

in my 2001 C320 I have a random series of clicking,, it only happens when the climate control is on auto.. or if i switch a certain zone,, what could this be and could i correct this?

mercedesdoc · #2 06-19-2004, 04:34 PM

Sounds like a bad stepper motor, Usualy the one behind console, requires to remove center console, benz sells a new one with new plastic gears and shafts. very time consuming

Gilly · #3 06-19-2004, 09:59 PM

I'd agree with that. The stepper motor is a small electric motor that controls the various flaps inside the dash for the climate control (there are a few of them). Another possiblity is that it's a problem with the small nub that the stepper motor connects to, in otherwords the end of the flap itself, not the stepper motor.
What a tech needs to do is a "synchronization" procedure to see if the stepper can be made to operate properly. If not they need to investigate which stepper is making the noise and if replacing the stepper motor will fix the problem or not.

Gilly

f4iman78 · #4 06-23-2004, 10:44 PM

Its common for the linkage for the footwell flap stepper motor to crack and cause that noise. There will most likely be a fault code in the acc system. Its a pain if you dont know what you are doing. Good Luck.

bender · #5 11-06-2004, 10:11 AM

Evan,
did you get the clicking noise fixed? There is another post here that discusses stepper motors failing too. Something about 10 servos requiring replacement and two days to do it.

My w203 has the exact same problem. I think it started gradually with faint clicking noises over the past year growing steadily in volume to the point now there is a loud thumping noise under the left of center dash location. Sounds like a linkage has "separated" and is impacting.

Evan · #6 11-06-2004, 12:43 PM

I never got that fixed, i hear it every now and then and when it happens it drives me up a wall!! i wonder IF Mercedes will take care of it even though my car is out of warranty

mslc791 · #7 11-27-2005, 06:19 PM

My '01 C240 just started this clicking, usually it lasts about a minute when the car is started. Is there a set of instructions on how to replace that faulty stepper motor(s). Please help.

Johnhef · #8 11-27-2005, 07:46 PM

I can talk you through replacement of it.

Is it a spaced out "click" noise with some silence inbetween each click or a quicker "rat-a-tat-tat" noise thats constant?

mbdoc · #9 11-28-2005, 08:38 AM

Not really a bad stepper motor BUT the linkage between the footwell control stepper motors. REPAIR kit lists for around $25, takes about 4-5 hrs.

mslc791 · #10 12-10-2005, 03:38 AM

Ther are about 5-6 clicks with pauses inbetween. The clicks appear to come from the windshield vents area, but only when the car is started. I just tested the air flow from various vents and besides the clicking after start, the system seems to operate normally. Any ideas?

Johnhef · #11 12-10-2005, 12:32 PM

sounds like the link arm.

ROGER E. · #12 12-11-2005, 12:00 AM

All this makes me so happy I extended the factory warranty on my '01 C320 before the first year was out. A paltry $2300 which I'll make back many times over, I'm sure.

Johnhef · #13 12-11-2005, 12:32 PM

Theres a lot to remove but if you take your time, you'll find its not too hard.

Remove the center console, center dash vents, radio, wood trim, etc and lower dash left side, from there you can see the arm behind the stepper motor, if it moves freely, theres your problem. The arm connects to the motor like a socket on a nut. Its a hex and the arm usually splits at one point causing the pop noise every few seconds when the motor tries to actuate.