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00 C-230, 04 C-240
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Discussion Starter #1
The A/C stopped working on my 2000 C230K. I'm glad it died now and not in August when it's 110F here. The A/C clutch is not engaging. The climate control is manual, the EC switch is OK, but the fan blower controller is starting to act up -- intermittent fan operation, but the fan still runs. Could this be the problem? Are there any usual suspects for no power to the a/c CLUTCH? And last but not least, anyone know where the A/C fuse is located, or what fuse block connects the circuit?

Your help is much appreciated.
 

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'99 2.3L Kompressor
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Do you ever get the flashing EC light right at first? If so, that could be the sign of low freon and the safety shut off feature. After that, it could be a number of things. I doubt a bad fan itself would send a signal that caused an error that would stop the clutch from engaging. If things froze up because not enough air was moving, that would be a different story.
 

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Discussion Starter #3
The EC light is working OK -- no flashing. I have done some searching and one possible problems is the evaporator temp switch, but I can't find test procedure for this switch. Another problem might be the temp switches in the engine bay.

Would you know where the A/C relay is located?
 

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I'm having A/C issues with my 99 C230K at the moment as well.

My wife was driving the car when the A/C compressor clutch coil burned up on it (nasty burned electrical smell and infinite resistance across the coil). I installed a new clutch on the compressor this week, but I haven't plugged in the power to the clutch yet because I tested the power terminal to ground and found I was only getting ~8.5V to the coil, hence the burned coil. I also found that it gets 8.5V when ever the ignition is in the 'on' position - EC button doesn't make any difference.

So I started looking for an A/C relay and it doesn't appear to have one. According to the diagram on AllDataDIY, voltage comes directly from the N19 module in the dash. Item A9 in the diagram below is the clutch.


I bought a used N19 module on ebay which I'm expecting tomorrow. I'll post back with my results.
 

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Discussion Starter #5 (Edited)
Thanks for the info. What part name did you use searching E-Bay for the N19 module, and where is it located under the dash? Did you take the voltage reading from pin #20 on the N19 module, or at the compressor clutch?

Looks like I have to dish out for the alldatadiy account. Again ,thanks.
 

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1986 190D 2.5 5 Speed
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I bet you need a new CCU. If the lead to the compressor is not getting juice, I and a lot of others have been through this, it is your climate control unit. Because it is manual, I am just guessing there is no reset feature. However, my guesses have been wrong before. Michael
 

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Here's one on ebay right now. Search 'climate control' under ebay motors 'parts & accessories' then narrow your search with 'Mercedes', etc.

BTW, you might also want to pick up a set of radio removal keys if you have the factory radio (or just stop by a car audio shop). You'll need to remove the radio and four screws holding the bezel to access the climate control unit.
 

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Discussion Starter #8
Thanks for the info. A bad CCU would also explain the funny blower fan operation. The fan seems to have a mind of it's own -- lower settings make it blow faster than higher settings, and this varies. At first I was thinking it might be the fan blower control unit that's causing this, but it just might be the rheostat switch in the CCU that's causing both problems.
 

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1986 190D 2.5 5 Speed
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Andrezejek,

Makes sense with a bad potentiometer for sure.

I have never seen a manual unit in real life. Are they modular or do you have to replace the whole unit? Michael
 

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Discussion Starter #10
Michael,

I'm not sure, but would bet that it's a whole unit. I'm wondering if a contact spray cleaner on the potentiometer would help?
 

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1986 190D 2.5 5 Speed
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Michael,

I'm not sure, but would bet that it's a whole unit. I'm wondering if a contact spray cleaner on the potentiometer would help?
I did not know North American spec CCU's came in manual. Let us know how the fix goes. Michael
 

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'99 2.3L Kompressor
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FWIW, I had my manual unit go flakey on me a few years ago while the car was still under MB extended warranty. They decided to replace it and had to replace the whole unit.

If I had to replace it again, I would consider using the digital unit instead as long as I could find the matching (color and lightness) wood trim piece to accommodate the digital unit. At least with the digital unit you could run the self diagnostics by yourself.
 

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Discussion Starter #13
I was thinking along the same line of replacing the manual CCU with a digital CCU if the existing interconnect would allow it. Something else to investigate. Did the stealer, I mean dealer, offer you that option?
 

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I was thinking along the same line of replacing the manual CCU with a digital CCU if the existing interconnect would allow it. Something else to investigate. Did the stealer, I mean dealer, offer you that option?
I'm going strictly by the alldata schematics here, but it looks like the pinout on the manual unit (n19) is completely different from the auto (n22). Note, for example, clutch is powered by pin 20 on the manual unit and pin 25 on the auto unit, etc.
Page 1 of N19:

Page 1 of N22:


I'm not saying it couldn't be done, just definitely not plug-and-play.
 

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Thanks for the info. Did you get a chance to plug in your CCU?
Yes, and the news isn't good:(. I plugged in the new CCU and still saw 8.5V with the clutch power lead unplugged. So I figured I had nothing to lose by trying it out at this point. Started it up with 'EC' on, ran fine with clutch disengaged, then tried A/C. Clutch engaged fine, but to my dismay I found that the compressor itself is toast. It sounded like it had rocks rattling around inside.

I had assumed that since I could turn the compressor clutch plate (connected directly to compressor input shaft) by hand, the compressor was okay.

WRONG!

Time to shop for a new compressor:(

Andrzejek, I've got a spare CCU if you need it!
 

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'99 2.3L Kompressor
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>>Did the stealer, I mean dealer, offer you that option?<<

No, I didn't ask though because I knew MB would only replace the part that came standard from the factory. Others have said they have done the conversion so it seems it is possible although you are going to have to get the other dash wood trim.
 

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'99 2.3L Kompressor
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Yetimus - that sucks. Your first post led me to believe you had already ruled that out. I have had the dreaded rattling/dying compressor before. About $1.5k worth of 'not fun' for me because I didn't have the equipment to attempt to do it myself. Sometimes I am smart enough to realize I need to leave a project to an expert (non stealership if possible) ;).
 

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Discussion Starter #19
Yetimus, I will be checking my CCU this weekend, as soon as I can figure out how to get the wood trim off, and keep my 3 & 6 year old boys out of the garage. I want to check the voltage out on pin 20. Also, I found the power lead going to the compressor had a bad kink -- it was aclually jammed between the brake lines that come out of the ABS unit. While driving to work this morning I heard a clicking sound coming from where the blower fan is located. The CCU fan speed was in the OFF position, and the clicking stopped when I placed the switch to ON. The CCU must be another great Lucas electric part!!

How much are you asking for the CCU?
 

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Compressor changed!

Well, I did end up wasting ~$130 on the new clutch on my burned up compressor, but I did the compressor change myself and I'm only out around $600 total. (reman compressor, filter/dryer, O rings, refrigerant, oil, new belts, and a few tools I needed). A friend of mine loaned me his vac pump and gauge manifold, so I was able to do everything but evacuate the system myself. It was my first attempt at A/C repair and it wasn't all that difficult, though it if fairly time-consuming.

Any luck on your end, Andy?
 
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