stgry1

I'm hoping someone can assist me with this. I have spent some time searching for this procedure through our forum and others but have been unsuccessful. Most of the threads on this revert back to W203 or older head units. The A/C operation on my vehicle is sporadic at best. The blower and all the functions operate as designed but the cooling of the system will not engage until 5, 10 or maybe even 30 minutes after driving the car. Sometimes it works just fine and begins cooling immediately. Prior to tapping the system to test for low Freon etc, I was wanting to perform a head unit reset as all indicators point to that from my observations. From researching the workshop manuals, there really aren't any relays or other areas to point a finger at for this type of malfunction.


Does anyone know this procedure for the 2011 model year? Thanks in advance.

Merserybenze

I have the exact same issue on my 2010 W204. I had it tested by an Indywho hooked it up to STAR. He refilled the refrigerant but could not find any issues. I hooked it up to DAS/Xentry and Vediamo and ran the AC tests but no issues. I still get the intermittent problem you describe. No idea how to reset the AC unit.

stgry1

Interesting....I don't want to crack the system and add Freon when it very well may be fine. Once it does function, it's blowing at 38F which is within spec. I'm sure it's electronic which is why I'm hoping to try a reset...if that even exists. I did read somewhere that there is a way to see the Freon level via the engineering screens but it wasn't on W204.

Merserybenze

i've read others with this problem replaced compressor and everything was okay. I wonder if that just 'reset' something? I don't want to spend so much without reason.

I also read it might be the temperature sensor in the dashboard in front of windscreen - again, inexpensive part but requires removing dashboard, so lots of labor.

Funny thing is when it happens to me if I turn AC on and off a few times it suddenly becomes cool. Other times it takes 5 -10 mins before it becomes cool.

Can't find a rational pattern or reason why this issue occurs.

stgry1

So I guess no one is familiar with this??

tuju77

Well I just had problem with my aircon. It only blowed hot air and sometimes working when I restart the car but mostly not.
Get the compressor replaced and worked for few km and showed the same problem again.
Finally get it scan and the error is in front sam module where it says climate control problem or something like that.
The mechanic replaced the pressure switch on the bottom and the aircon worked wonderfully but sometimes still showing the problem and its gone when I restart the car.
The mechanic told me that the front sam has error but not a fatal one.
Can anyone suggest what to do?