Hello everyone. I have a problem with the A/C on my 98 CLK320. Here's the 411.

I turn on the A/C and the compressor engages. After a few minutes, the compressor will disengage and will stop blowing cold air.

The only way I can get the compressor to engage again is to turn off the car and wait for about 30 sec to 1 min. You'll hear a "tick" sound. After that, I can turn on the car and A/C again and the same problem will occur in a few minutes.

What's strange is that even if I turn off the A/C for an hour or more, and turn it on again, the compressor will not engage unless I turn off the car as I described above.

I read in the manual that the EC light will remain ON if refrigirant is low. Mine didn't do that but I took it in to get it checked out anyway. They added some 134a and also told me the pressure was fine.

Any help would be appreciated.

Thanks in advance,
JL

There is a lot in recent (and not so resent) archives on both your symtoms and some diagnostic processes.

The main thing is to use your display as an instrument to find the problem. By pressing the "REST" button until a "1" appears on the left, you have entered actual values. Go to the archives for the list of values but by hitting the two "AUTO" buttons one can scroll up and down with item #5 being evap temp. My most common fault for your symptom would show the evap temp sensor at 150deg or more...not a likely event and the controler won't put up with it and withholds AC function.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

You are absolutely right. The evap temp showed 150deg. I turned on my A/C. It was blowing cold air for about 3 minutes and the compressor disengaged. I checked the evap temp and it showed 156deg.

I guess my next question is how much will it cost to change this sensor. Can I do it myself? Could there be another problem which results in the incorrect evap temp reading other than the faulty sensor itself?

Thanks for all your help.

No.... it always is the sensor. MB has recently changed the number on it to 210 830 07 72 from 05 72. Just replaced one on a 140 car yesterday.

As to whether you could do it, I can't say. I couldn't do it, but I'm 55 6"4" and overweight. I got somebody else to do it for me though, and they can do it in about ten minutes with only two to three scratches reaching blood (bg). It is on the top left front of the evap case. One must go in at the gas pedal and reach up and over sort of.

BTW the Change in number did change the price as list price is now $53, where it used to be $35 under the old number.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Thanks for all the help. I really appreciate you taking the time to help me out.

So, the evap temp sensor is in the same location in the 208 as the 140? Is there another way to get to it besides going through at the gas pedal?

Thanks again.
JL

The description was actually for a 210 chassis, the 140 is much easier. Haven't done one on a 208 but I presume it would be similar to a 210.

And if there was an easier way, we would naturally use it. if you take the dash off it would be right there.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician