Hi,
I have a 1996 w210 with an aircon pushbutton switch or an Automatic aircon.

When I turn on the aircon, the blower and compressor works fine blowing in cold air from the center vent and right and left vents.

My problem is, without pressing anything on the Aircon switches, the Aircon shuts down the blower air from the center vents and goes into defogger mode by itself!! This means cold air from the right and left vents and the vents above the dashboard for the windshields!!

Hmm,. what is wrong with it? the switch??

Anyway, the aircon goes back to normal sometimes when I shut the aircon off or press recirculate button.

I hope this is not an expensive problem.

Thanks for any help.

 

I would look for a vacuum leak.
Phil

 

I have 99 model I after studying the manual, have learned that the system determinate on its own where to put the air in certain situations and temperatures. The only thing the driver can force out of it is defrost mode, or switching to manual.
I just hate cars, that trying to be smarter, that I am.

 

Might want to check out this guy's solution:https://mercedesforum.com/m_25536/tm.htm. Sounds a lot like your problem.

 

Thanks.

As of now, the A/C vents are working properly although I haven't done anything yet.

I also noticed a whole colony of ants lived inside the car. I discovered them inside the sunroof mechanisms and some on the dashboard!! I think they might be doing something to the A/C switch. grrrrrr.

 

i have 190e model 1993. aircon continue running even switch off.please somebody help me what i will do