[wheelz]

My A/C works when it feels like it, usually when the weather is too cool to need it and then just for a while. System refrigerant pressure shows good. The compressor clutch just does not turn on except rarely. When the compressor is turning everything is fine, nice cold air. I have not found a way to influence this except by a change in weather. I have replaced the climate control system with two other used units and no difference. I would consider wiring the clutch to a manual switch if I knew which wire controlled it. Anyone else seen this problem?

 

[wichipong]

have you tried the blower regulator?

 

[wheelz]

The "air volume" controls 1 thru 4 work fine, so does the AUTO mode. It usually just blows hot air even with the temp setting at "LO", unless I get lucky and the compressor clutch operates for a bit.

 

[Metafly]

The "air volume" controls 1 thru 4 work fine, so does the AUTO mode. It usually just blows hot air even with the temp setting at "LO", unless I get lucky and the compressor clutch operates for a bit.

I have had this issue. What solved it for me was resetting my CCU computer multiple times (it took at least 10 resets as I recall) I will look for the procedure but it is on here someplace. Michael

 

[wheelz]

Today was 55 deg out. Had climate control on 74 and everything worked fine, compressor was working. If temperature was 70 deg or more outside, it would only be blowing hot air no matter what the setpoint was.

I'm interested in trying the CCU reset if you find directions. Thanks!

 

[Metafly]

I believe this is it: http://glenet.net/mercedes/W202 VERSION CODE.pdf

 

[wheelz]

Wouldn't you know - model year 1995 is totally different unit. I guess I could poke around and see if I can get it into a programming mode, really can't do any harm since it doesnt work anyways. Thanks for looking this up.

 

[Metafly]

Those instructions work just fine - I have a 94

 

[doin12volt]

Well, I would check the obvious first. Put a Volt meter on the 12V wire that engages the AC clutch to see wether the +12v source is turning on and off randomly, or wether +12v needed is staying present but the clutch is not working - this will tell you if it is a bad clutch (yes they go bad - they are just electromagnets) or weather this is a logic control problem turning the clutch on and off at random times.

 

[wheelz]

Just tried it - you're right! It went into program mode. 01 gave me readout in deg C, 02 gave me readout in deg F. I'll keep it there for now. Tomorrow should be warm enough to see if it works. Thanks again.

 

[vilemd]

how and were do you find the ccu directions?!?!?

i just bought a c220 95, for only 600 bucks. what a deal. anyways when i test drove it and it was cold out it felt like the ac was working but not that well. now that its warmer out(im in FL) the ac dousnt feel like it cools at all. id like to try the reset thing if anyone has more info on it

 

[engine89]

Have you tried adding some 134A to the system ? The compressor won't kick in if its low

 

[vilemd]

yea, i did before and nothing happened but it was what was left in the can. i did just put some more in and it finally kicked on. i thought there was a leak so i put some stuff thats supposed to stop it from leaking and it didnt really help but now atleast i know the problem is a leak somewhere, sounds like its near the front of the compressor side but im not sure. guy wants 280 labor alone to replace it. gona have to find the leak myself i guess

 

[engine89]

my 95 c220 was leaking through the sight glass on the reservior/drier. I changed it and refilled its been great since.

 

[kristijan920]

My AC just stopped working
Month ago it worked very well
EC doesn't light so compressor IS working but air is hot.(manual climate control)

suggestions?

 

[baheej]

Hello Sir, the link you copied here does not work, please check I need this link

 

[Franklyspeaking]

Just because the EC light is lit does not indicate the compressor is operating. When the EC light is on it is not operating, because the EC circuit turns it off. There are other sensors that will turn the compressor off also, namely Hi/Lo pressure & temperature sensors. Hooking A/C gages up to the ports is the best way to tell what is happening. As an alternate, if you have the Electronic climate control, you can put it in diagnostic mode and read the sensor values. Do a search.