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Discussion Starter #1
I am not sure if this thread was posted previously, but I am a new user and am not very sure how to use this site. So anyway, today in blazing hot SoCal (Southern California) I finally replaced my W210's blower motor resistor (early model). The resistor was not sending enough power to the blow motor so in effect not blowing enough air. Read online and seen that alot of people replaced it with the W140 regulator and voila blower works flawlessly. When I purchased the vehicle the resistor was bad so i never really knew how a Mercedes-Benz A/C felt at full speed. Anyway so after a couple minutes i notice that the Air conditioning felt cool but almost as if it needed freon. Silly mistake on my part; I go to autozone and purchase the freon BEFORE checking how much freon is already in the system. (Had the tool in my trunk). I plug it up and it immediately jumps to red so i didnt bother but auto zone wouldnt replace it because i had already screwed it into the tool. So at that point i decided to look down at the compressor and to my surprise, it wasnt turning at all. It was weird because before i replaced the regulator the compressor was definitely on. So I shut the car off and head into auto zone again to ask some questions about why the compressor wouldnt turn on (I know noob mistake I was desperate) and then i go back outside and turn the car on and the A/C is throwing ice cubes in my face! Amazing! But then shortly after the compressor shut off again. I noticed that everytime i shut the car off and turn it back on, the above repeats itself? Can anyone help me? Its going to be 90+ degrees the rest of this week and I would really like to get this thing fixed. Sorry for the long post. Thank you in advance
 

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Discussion Starter #3
I believe I can't run this test as i have the issue in a W210 not a W140. I have a W140 regulator in there as mine blew out
 

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Okay I've noticed something new. I check the low side pressure and noticed it actually is considerably high. Could the compressor be shutting itself off as a safety feature?
 

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Okay I've noticed something new. I check the low side pressure and noticed it actually is considerably high. Could the compressor be shutting itself off as a safety feature?
It would be high if the compressor was off, when on the low pressure decreases and high pressure increases. You need to run diagnostics to find out what is switching the compressor off, see my post above.
 

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Discussion Starter #7
I will run these test and post what I find. Thanks. Also the display for the a/c control module is a bit messed up in the right corner so I'm not sure if I'll get a good reading with the dtc codes. I'll post what I find
 

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Discussion Starter #8
Don't mean to ignore your comment Eric. We ran some test and singled it out to the actual fan itself. I was completely oblivious to the fact that the fans never even kicked on with the ac. I ran a current test and seen that power was being sent to it to trigger the fan but the fan never responded and the fan on the other side was always spinning. Turns out it wasn't attached to the belt so the air from the engine fan was moving it so I assumed they worked. Anyways I ordered the part and we are patiently sweating I mean waiting for it to come haha. In the mean time I have to drive a dreaded bmw to keep cool ;(
 

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Don't mean to ignore your comment Eric. We ran some test and singled it out to the actual fan itself. I was completely oblivious to the fact that the fans never even kicked on with the ac. I ran a current test and seen that power was being sent to it to trigger the fan but the fan never responded and the fan on the other side was always spinning. Turns out it wasn't attached to the belt so the air from the engine fan was moving it so I assumed they worked. Anyways I ordered the part and we are patiently sweating I mean waiting for it to come haha. In the mean time I have to drive a dreaded bmw to keep cool ;(
Having to drive a BMW, oh the humiliation.:biggrin:
 

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Discussion Starter #12
Okay Eric since you have helped me throughout all of this I decided it would be fair to update you with what has been going on. At this point me and the mechanic are doing trial and error replacements to single out the issues with the A/C. Now we have replaced the pressure switch and the evap temp switch just to replace any sensors that may be tripping off the system. That didn't work so we got another mechanic in to check it out. He was stumped but diagnosed the compressor as the issue. We got a compressor from a working E320 from the same year, 97, and replaced it. That didn't work either but didn't upset me to much as I only paid 60 bucks for the compressor. So now after eliminating all of those possibilities I'm starting to thing the actual control module is our issue. Because it was only AFTER I did the W210 to W140 regulator swap. I think it could have tripped something out in the controls. Anyway going to see another mechanic that works with these kinds of issues and will post the solution. In the mean time, I still have to drive that darn BMW to keep cool. So sad. They never realized what true performance was.
 

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Discussion Starter #17
I'm not sure on how to check that, but I recently had it topped off by an A/C shop to check to see if that was my problem and it wasn't. But I left the freon in
 

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You will need the pressure guages attached to the system to read the pressures, reason I mentioned this is that the high pressure may be too high due to a blocked/broken expansion valve. A local workshop of any car repair type will have the guages.
 

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Discussion Starter #19
I've heard something about the expansion valve mentioned before on a forum. How much does it cost to replace that?
 
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