My wife's ML has just satrted to make a strange noise in the adsh which seems to be related to the HVAC system.

When the temperature control is on its coldest position, there is a tick tick noise from near the center vent about once per second. If you advance the temparature control 2 "notches" above the coldest setting, the noise goes away.

The position of the directional setting seems to make no difference. Do I have a jammed vent door or something??

Gilly??

Sounds like a problem with the blend door stepper motor. Common problem on the ML's, list price is $35.50. Somewhat labor intensive as the dash has to be removed for installation.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks MB DOC, I thought it was a vent or motor problem.

How much of the dash has to be removed to replace it? Is it likely a repalcement item or a "lube" might fix it?

Thanks again.....

Hi MBDOC;
Maybe you can help me. Can the airmix control unit(potentiometer) be installed through the instrument cluster?
If so any special tools required?The mercedes mechanic isn't sure here and of course I do not want to remove the dashboard.
I really appreciate your help!
Roberto

MBDOC;
Forgot to mention it is a 1993 190e 2.3.
Roberto

Roberto,
ON the W201 chassis (190's) the dash MUST be removed to install the feed-back potentiometer.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks for your reply MBDOC. The CD manual says that it can be installed through the instrument cluster. I would like to know for sure before I give the mechanic the greenlight to go ahead.
Have you tried this procedure before?

We also have to replace the heater valve shutoff unit in the console and hopefully this will solve the no heat problem.
Ever seen this problem before on the 201?

I have installed at least 50 feed-back potientiometers ON W201 cars, ALL required removal of dash!!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

MB Doc

Any idea of the labor hours involved to remove enough dash to replace that stepper motor? Can you tell me which bits have tobe removed?


Roberto

I did not like you hijacking my thread since I still have some questions..... and you had to jump in and ask your own when you already had a thread running. I hope all your chickens run into each other and you get no eggs next week!

sorry about that. Just had a frustrating car problem and wanted mbdocs opinion!
Goodbye and take care.