W205 Mercedes C220 2015 Air Con Clutch

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Churchy29

New Member
Joined
Apr 28, 2019
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10
Location
Sheffield, UK
Car
Mercedes C220 Amg line W205
Hi Guys!
I have a Mercedes c220 blutec W205. A few weeks ago the air conditioning stopped working and so I took the car in for a re-gas.... only it turned out the gas is full and there is a problem with the clutch on the ac compressor not engaging. I have tried quite a few remedials with no joy!
It could either be the clutch itself or electronics I am told. It does work intermittently and has engaged a few times when I have had the bonnet up but it doesn’t seem to fully engage.
Anyone had the same issue? Do you think a new clutch ?
 
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Hi Guys!
I have a Mercedes c220 blutec W205. A few weeks ago the air conditioning stopped working and so I took the car in for a re-gas.... only it turned out the gas is full and there is a problem with the clutch on the ac compressor not engaging. I have tried quite a few remedials with no joy!
It could either be the clutch itself or electronics I am told. It does work intermittently and has engaged a few times when I have had the bonnet up but it doesn’t seem to fully engage.
Anyone had the same issue? Do you think a new clutch ?

I also have a 2015 plate W205 and from my VIN decode it shows that the aircon compressor has a magnetic drive coupling rather than a clutch type system. Someone more knowledgeable should be able to help more.
 
I also have a 2015 plate W205 and from my VIN decode it shows that the aircon compressor has a magnetic drive coupling rather than a clutch type system. Someone more knowledgeable should be able to help more.

Thanks for that. I wonder if it could be electronic if it’s an electro magnet type coupling - the car is booked in for the £150 diagnostic visit at the merc dealers! I’m hoping it’s a cheap fix
 
im just back from a break and my car is still pretty stripped in my drive so I cant help much but rather than just forking out all that money for someone to look at it can we get some info on power supply / plug / fuse or relay number and location.
a proper auto spark would take half that amount to tell you if power supply is ok and if all is well and you need a clutch then they are available Buy Compressor Clutch for MERCEDES-BENZ C-Class Saloon (W204) C 220 CDI (204.008), 170 HP (year from 2007) cheap online.

I can look tomorrow take some pics if its same setup and check if its battery voltage supplied to clutch mag
 
again for info only
how does an aircon clutch work - Bing video

its same but different as I use on electric motors on materials handling equipment, as a magnetic parking brake its basically a simple wound copper winding that magnetises when voltage applies to mate with adjacent metal back plate and squeeze

these will work or wont work so I guess you have a loose or dirty plug connection or faulty relay as you have stated that it intermittently works.
good luck
 
sorry I picked the w204 but the w205 is there on that site too
different part number and size but same principle
 
Thanks for your help on this Robster - due to Mercedes Benz of Sheffield not booking me a courtesy car - they haven’t looked at the car yet and so I am not £200 lighter (yet).
I stuck a voltage meter on the air con contacts and no voltage / intermittent spikes and so I imagine you are right re the relay or faulty connection.
The only problem is I have no idea where the relay is and so any help to locate this would be appreciated. I will take all of the plugs out and clean them up later today.

Thank you

Also I will send some photos over later.
 
So after taking the car to get a new tyre today - the guy at the garage looked at the problem and quickly noticed the engine cooling fan was on constant. He suggested this will be down to a faulty air con pressure sensor and hence my air con is not working / clutch is engaging.
This seems most likely as I’ve noticed with the air con off the engine coolant fan is running constantly- apparently the systems are linked.

I am struggling to locate the air con pressure sensor so any help would be appreciated. I am aware the gas needs emptying before changing this but was going to try unplugging and cleaning contacts.

Thank you
 
you got an owners manual ?
mine shows you where all the fuseboxes are on p361 ( for the w204).
unfortunately mine doesn't show fuse and relay allocations in book
but would hope by removing fuse covers that there is a legend printed on the cover showing what fuse and relay does what.
good place to start.
a quick test I like to do if possible is swap relay with another matching relay in the fuse box to see if fault transfers to that circuit telling you the relay contacts have gone bad
 
Aircon px switch is located on the lower corner of the condenser which is in front of the radiator. New one is about £40. An indie fitting and regas with be about £160
 
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Thanks, just looked at fuses and relays all okay. The engine cooling fan constantly runs as soon as the engine starts - it roars up. I’m sure that there must be a temperature sensor / connection between the cooling fan and the air con not working.
It looks like I have no choice but to get it diagnosed at the dealers.... luckily they have emailed me today to apologise and given me a diagnostic for free. I will keep you updated.
Thanks
 
When I asked a question about my air con pump on here some years back I was told and guided to a video explaining that the compressor has no clutch. It runs all of the time , the pulley directly drives a disc and the angle of the disc is altered depending on demand causing the pistons in the compressor to work harder when cooling is required. This type of compressor (Bosch ?) requires the system to be charged all of the time as the fluid/gas is required for lubrication even when the compressor is not in use as it is spinning all of the time the engine is running. Someone on here will have the answer.
 
Thanks Petrol Pete, the W205 has a magnetic ac clutch - and only spins when ac on. I’ve figured out using the voltage tester on the clutch contacts that the fault is electrical. However I believe there is some link between the cooling fan running constantly and the ac not working.
 
You do know that if the AC pressure drops below a certain level (leak) the system will shut down to protect itself from lack of lubrication normally provided by the fluid. Basically switching the clutch function off. ?
 
You do know that if the AC pressure drops below a certain level (leak) the system will shut down to protect itself from lack of lubrication normally provided by the fluid. Basically switching the clutch function off. ?

Hi, first thing I checked and the gas is full. This is a mystery but the car is booked for diagnostic Monday and so I will update you all.... my bet is faulty pressure sensor
 
Update guys - Mercedes have had the car in and it was a faulty pressure sensor plus a break in the elec cable to the pressure sensor.
I now have a cool car and the cooling fan is no longer running constantly..... just £285.00 down
 

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