Hello,

I have a 98 c230 with 100k Miles. A couple months ago I noticed condensation building on the inside of my windows and I couldn't get the defroster to remove it. A quick look revealed that the AC compressor wasn't kicking in.

I added Freon and oil; gauge reads 35 psi on the low side. No Change. The strange thing is when I first turn on the car it works for a few minutes then stops.

My mechanic said it was the Climate Control Unit causing the problem. So I bought a new one from a dealer and replaced it. No change.

I connected a hot lead to the AC clutch and forced it on, and it worked great. I temporally connected a toggle switch so I could turn it on manually. I am now assuming that it is an electrical problem not an AC problem.

Does anyone have any ideas or suggestions?


Thanks in advance.

Jarboe

Run the actual value test through the control head. Pay particular attention to the evap temp sensor. If it reads 150 degrees replace it. if one does this test after the car has sat a while (like overnight) the first 5 or six sensor values shouls all be the same (ambient temp naturally)

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

Steve,
Thanks for the help. I just performed the Actual Values test and here are the results:
1 101
2 81
3 88
5 162
6 77
7 060
8 77
9 32
10 495

5 is the evap temp sensor right? Do you mean if it is 150 degrees exactly replace or if it is over 150 degrees replace it? I haven't driven the car at all today so there was no reason for it to be this temperature.
P.S. do you see anything else that looks off?
Thanks,
Jarboe

The #5 reading is clearly wrong. That will prevent the compressor from starting. "150 degrees" is simply shorthand here for an unbelievably high reading, which is what you have.

Ditto, I haven't seen one above 155. Definitely beyond the limits of plausibility.

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

Thanks for your help. I had the evap temp sensor replaced and all is good.

Sincerely,

Jarboe

Steve,
Thanks for your time on the phone. Just to let you know, I tried the test and received 161 degrees on number 5 ( evap temp ). Is that a record?