A/C is not blowing cold

[Dr.Drew]

For the first time this year i turn the A/C on I am getting no cool air, any commen problems on the W202 with the A/C system

[jnenad16]

common problem with all cars is that they leak out freon. honestly, there could be just about everything wrong with the ac system for it not to cool. could you describe the symptoms in detail, such as does the rpm change when you turn the ac on, does it cool at higher rpm's, it the ac temp different between the vents or is it the same...

nenad

[Dr.Drew]

vents all blow the same ammount I was on a 6 hour road trip yesterday no cooling at all all rpms there is a part on the front of the compressor should it be spining with the rest ?

[jnenad16]

yes, the front of the compressor, the clutch, should be spinning together with the compressor. if it doesnt, it could be one of the three things:
either you are out of freon, or
the control unit might need replacement, or the pressure switch is defective.
if the clutch is spinning, tnen the most likely cause it a stuck expansion valve or a plugged filter/drier.

nenad

[Dr.Drew]

clutch isnt spinning, put the car up in the air and looked that clutch is not spinning i checked the fuses and what else should i look at ?

[Ashkan's C280]

low coolant and pressure?

[Dr.Drew]

what version of freon are these cars running ?

[jnenad16]

Originally posted by Dr.Drew
clutch isnt spinning, put the car up in the air and looked that clutch is not spinning i checked the fuses and what else should i look at ?
if you have the ac gauges, you can check the system pressure. it should be around 100psi at idle for the clutch to engage. if the pressure is good, and the clutch is still off, then check if you are getting the signal from the control unit by unplugging the compressor connector and check the red wire for 12V. if voltage is present, then the clutch needs to be changed, if no voltage, the control unit(actually a module within the unit) is defective, thus the unit needs to be replaced, unless you know of a shop that can rebuild them.

nenad

[Dr.Drew]

could you explain more about the 12volt source on the compressor all i can find is one wire on the compressor

[jnenad16]

whats the year and model of your 202?

nenad

[Dr.Drew]

1997
it had the faulty 5 speed in it.

[jnenad16]

Originally posted by Dr.Drew
1997
it had the faulty 5 speed in it.
is it a 230, 280 or 36?

nenad

[Dr.Drew]

C280 sport

[jnenad16]

ok, you should have a connector with three wires connected to the top of the compressor. there should be red, white and a green wire. the red(i think) should be the supply line. however, when you go to check for voltage, test all three wires as the setup might be different on the 97, but esentially works the same as the earlier models.

nenad

[Dr.Drew]

not seeing anything other then one green wire ?

[jnenad16]

I guess thats it. try unplugging it and test for voltage.

nenad

[Dr.Drew]

a/c condenser is gone anyone know where there are good deals online for one ?

[jnenad16]

www.germanstar.net
www.thebenzbin.com

nenad

[Dr.Drew]

got my condenser but am haveing trouble getting it out any tips ?

[Dr.Drew]

got it out now the trick is to get it back in theres no easy way

but they sent the wrong one


how do you check the tranny fluid i have my own dipstick

[mr. gatsbury]

nenad,

my a/c is blowing a little bit cool but doesn't get cold. like a little cooler than just a fan blowing. the rpm's seem fine. do you think it's the filter? where do i find the filter to check it...

john

[Dr.Drew]

I dont think that the filter would prevent it from getting cold

[locopr31]

I have a question also on my AC. But first I want to say thank you for helping me out with teh MAF censor. My Ac goes on and off when i am driving. i think it could be a loose connection. But the problem I am seeing is that i am running out of anti-freeze. I don't see a leak anywhere or spots under the car. Could it be that it only leak when the presure is high. Or when i am driving. Can you advise on that.

Thanks

Zeke

[mr. gatsbury]

Originally posted by Dr.Drew
I dont think that the filter would prevent it from getting cold

what do you think it is then? I had my a/c stuffs flushed last summer...?

[Jasonmarosi]

this question is in lew to what jnenad16 mentioned about the 12V source.

I have on wire and tested it I dont have 12volts, I have like 0.7 volts. Where could this small voltage come from and I checked fuses they are ok. Is there a relay somewhere? I am currently checking to see if the system will maintain a charge. (clutch not spinning) Thanks

[jnenad16]

Originally posted by Jasonmarosi
this question is in lew to what jnenad16 mentioned about the 12V source.

I have on wire and tested it I dont have 12volts, I have like 0.7 volts. Where could this small voltage come from and I checked fuses they are ok. Is there a relay somewhere? I am currently checking to see if the system will maintain a charge. (clutch not spinning) Thanks
whats the year and model of your car?

nenad

[Jasonmarosi]

Originally posted by jnenad16
whats the year and model of your car?

nenad

1996 C220

[jnenad16]

if you have older style control unit, you should have three wires at the compressor clutch connector. one of these should have 12V when the ac is on. if no voltage is present, then its the ac control unit. if you have a newer ac control unit, then according to the diagram, there should be only one(?) wire, which theoretically should provide 12V to engage the clutch.

nenad

[Jasonmarosi]

I have the newer control unit and I have one wire on my compressor. But Im still not getting that 12V of pwr there. So far its keeping its charge day 2.

[jnenad16]

have you checked the fuses. also, have you checked the system pressure? it should be minimum 50psi with ac off, otherwise the pressure switch will keep the circuit open and control unit wont trigger the clutch. if you have sufficient pressure, then you are looking at a bad control unit.

nenad

[Jasonmarosi]

Originally posted by jnenad16
have you checked the fuses. also, have you checked the system pressure? it should be minimum 50psi with ac off, otherwise the pressure switch will keep the circuit open and control unit wont trigger the clutch. if you have sufficient pressure, then you are looking at a bad control unit.

nenad

Thank You Alot! I will check all that ASAP
Also wanted to add that the EC button lamp on the control unit stays on ALWAYS no way to change it but I hear the flaps close inside the dash.

[Jasonmarosi]

I jumped my Compressor and found that it works the clutch and all. I didnt run it for long becuse I have around 25psi of pressure in the system last week I had around 55psi So I have a leak. I may also have a bad control unit. I am going to replace the control unit and get the leak fixed and then recharge it. Then see how things go.