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Old 02-26-2011, 03:51 PM   #1 (permalink)
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Date registered: Feb 2011
Vehicle: 2000 c230 kompressor
Location: SW Mississippi, USA
Posts: 11
C230 ac compressor not coming on

Hi I bought my daughter a 2000 C230 Kompressor about a year and 10,000 miles ago - 120,000 miles now.

Monday the ac quit working the econ red light is on and will not cut off. This car has the manual ac with the two scrolling wheels to set temp - NO digital display.

Upon inspection, the compressor does not kick on at all. You can turn the clutch by hand?

The low pressure switch on the dryer has three wires - How can this be bypassed to make the compressor kick on so I can check the pressure? Or is there another way to make the compressor kick on?

I would like to work thru this myself if possible. Any suggestions?

Thanks
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Old 02-26-2011, 07:11 PM   #2 (permalink)
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Date registered: Oct 2007
Vehicle: 1998 c230 153k Center vents working again...Finally
Location: Exit 98, New Jersey, U.S.
Posts: 1,319
Your at a bit of a disadvantage without the digital CCU, Regardless would do an OBD scan at the very least and get a guage set on the sys. to check pressures. If possible get a can of leak dye detector and put that in. Would suggest not trying to bypass any sensors since its shutting down most likely due to low pressure (freon) and you could risk damaging the compressor. B
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Old 02-27-2011, 04:16 AM   #3 (permalink)
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Date registered: Feb 2011
Vehicle: 2000 c230 kompressor
Location: SW Mississippi, USA
Posts: 11
I can't get an accurate reading since the compressor will not run. However, I just put my gauge on the low side - compressor not running, of course - and the pressure with it just sitting there is 80 psi. Since the sheet that came with my gauge says that around 30psi is an appropriate reading with the compressor operating, I suppose there is enough pressure that the low pressure switch should not be shutting it down.

I can access and check the static pressure without the compressor running on the high side if that would help?

If everything is fine with sensors, etc. and the compressor is bad, would there still be 12V in the wire to it? Even tho the red econ light is on? I might be able to check it for 12v but figured with the econ light is on there's no power to it anyway.

If the compressor locks up, how does the system know such that the clutch disengages and doesn't destroy the fan belt?
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Old 02-27-2011, 01:59 PM   #4 (permalink)
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Date registered: Oct 2007
Vehicle: 1998 c230 153k Center vents working again...Finally
Location: Exit 98, New Jersey, U.S.
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Yes, check the high side as well, the pressure on either side will vary with ambient temps. If there is zero on high side there is possibly is a restriction and freon loss.
You might be stuck bringing this in because of lack of codes to work with for diagnosis. Some of the other somewhat common replacement items are evap temp sensor (under the dash), low pressure switch(you already found), etc. it is possilbe to jumper them but do so at your own risk, would not advice doing.
To answer the question about voltage, voltage is not supplied to compressor when its in shutdown mode, the circuit is not complete.
To answer question about the clutch if compressor seizes, there is a high pressure switch on the compressor, if pressure backed up since the compressor stopped the switch would cut off and disingage the magnetic clutch so it probably would not destroy the belt. Please fill out your profile. thanks, B
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Old 03-01-2011, 05:20 PM   #5 (permalink)
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Date registered: Feb 2011
Vehicle: 2000 c230 kompressor
Location: SW Mississippi, USA
Posts: 11
Well I decided to drive the car to work this morning. I cranked it up and I pushed the econ button. The light went off and the compressor cut on. I've no idea why. The outside temp was about 46. It worked on the way home tonight too. All together that was about 30 miles of driving. I don't get it. I was going to check the pressure but my daughter left in it. I'll be to tired to mess with it when she gets back. I'll check it first chance I get.
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Old 03-01-2011, 05:43 PM   #6 (permalink)
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Vehicle: 1998 c230 153k Center vents working again...Finally
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I am glad its working and perhaps you dodged a bullet for now. If it happens again it may be the climate unit itself or a temp sensor issue or thermister (these are put in the vents), I would check the readings on the high and low side when you get a chance to cancel out the possible low fridge issue. B
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Old 03-02-2011, 02:13 PM   #7 (permalink)
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Date registered: Mar 2010
Vehicle: 2000 c230 Kompressor (Totalled 5/2012)
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If it's working now, I think you'll be ok. Check the low-side pressure again while it's running and then the static pressure when the car is off. The AC system doesn't work intermittently: it either runs or doesn't run and there are sensors to try and prevent damage. I agree that if it happens again, it might be something electrically related.

If the pressure is low, I'd consider adding some refrigerant since there is an optimal amount for the system to run its best. In the future, make sure to run the AC at least once a week, regardless of whether it's winter or summer. Running the AC keeps the lubricants flowing in the system and will lessen the chances of things drying out.
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Old 03-02-2011, 04:54 PM   #8 (permalink)
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Date registered: Feb 2011
Vehicle: 2000 c230 kompressor
Location: SW Mississippi, USA
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I appreciate the help guys. AC is still working normally today. I checked the pressure when I got home with it running and it was between 35 and 40 psi, which ought to be about right as I understand it.

When it quit was only about the second or third time the econ button was ever pushed... Kinda makes me wonder if there's something wrong with the switch.

I pushed the econ switch when I drove the car to work last Monday morning. When I left Monday afternoon, I could not get the light to go off and the ac working by pushing the econ switch.

Last edited by rodneygt; 03-02-2011 at 04:57 PM.
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Old 03-03-2011, 12:28 PM   #9 (permalink)
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Date registered: Jul 2010
Vehicle: 1995 C220
Location: Missouri, USA
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A little late getting to this, but I was going to suggest it was the switch and not compressor or freon related. If eco lite is on, it will not call for ac no matter what you do. It could be you have some switches that are sticking a little. On my 95, for the longest time there were 2-3 buttons that when presssed, did absolutely nothing. One of them being the eco, the other being the rest button. I would just play with them once in a while when driving until finally, they started working, and have been good ever since.
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