A/C on-off button doesn't turn off the AC
09-13-2011, 11:43 AM
#1
Super Member
Thread Starter
A/C on-off button doesn't turn off the AC
Any one ever have this problem?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
09-14-2011, 12:43 AM
#2
MBWorld Fanatic!
Join Date: Feb 2004
Location: SEATTLE WASHINGTON USA
Posts: 3,986
Likes: 0
Received 5 Likes
on
5 Posts
'08 C300 Lux Barolo Red Beige Leather P2 MM 18" wheels '84 944
Any one ever have this problem?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
As to switching dealers, the service departments don't give a damn. You are revenue rolling in the door which is all that matters. What you won't gain, over time, is the status of "regular customer" if you don't stick with one store and believe me, there is a difference.
As to warranty repairs, dealers make good money on these since MBUSA pays for the parts and shop rates for the labor. They love warranty jobs and since the W204, W212 and W221 have hit the streets, warranty repair orders are far less to the point the MANY techs have been laid off. One big California dealer had been running two shifts because of the W203 and W211 and they finally let the whole night shift go because of the drop in warranty work.
My dealer likes to call in cars that about to go out of warranty, like mine and yours, and mine goes in tomorrow (no cost to me) to see what they can find. I'm providing a short list of things I know they will remedy.
The only hits taken in the service department are by techs when there is a comeback which is fixed on their time.
The following users liked this post:
sweseman (06-04-2021)
09-14-2011, 10:27 AM
#3
Super Member
Thread Starter
First of all, your AC system. You will never hear or feel the AC compressor engage because compressor clutches were abandoned at least ten years ago by MB and replaced by swash plate compressors. When you press the AC button to shut off AC only, the vanes in the compressor move slowly to the closed position and that's why cooled air continues to flow for a short time. I have observed that turning the AC back on (by touching the Auto button) it does seem to act faster. But, it's all normal.
As to switching dealers, the service departments don't give a damn. You are revenue rolling in the door which is all that matters. What you won't gain, over time, is the status of "regular customer" if you don't stick with one store and believe me, there is a difference.
As to warranty repairs, dealers make good money on these since MBUSA pays for the parts and shop rates for the labor. They love warranty jobs and since the W204, W212 and W221 have hit the streets, warranty repair orders are far less to the point the MANY techs have been laid off. One big California dealer had been running two shifts because of the W203 and W211 and they finally let the whole night shift go because of the drop in warranty work.
My dealer likes to call in cars that about to go out of warranty, like mine and yours, and mine goes in tomorrow (no cost to me) to see what they can find. I'm providing a short list of things I know they will remedy.
The only hits taken in the service department are by techs when there is a comeback which is fixed on their time.
As to switching dealers, the service departments don't give a damn. You are revenue rolling in the door which is all that matters. What you won't gain, over time, is the status of "regular customer" if you don't stick with one store and believe me, there is a difference.
As to warranty repairs, dealers make good money on these since MBUSA pays for the parts and shop rates for the labor. They love warranty jobs and since the W204, W212 and W221 have hit the streets, warranty repair orders are far less to the point the MANY techs have been laid off. One big California dealer had been running two shifts because of the W203 and W211 and they finally let the whole night shift go because of the drop in warranty work.
My dealer likes to call in cars that about to go out of warranty, like mine and yours, and mine goes in tomorrow (no cost to me) to see what they can find. I'm providing a short list of things I know they will remedy.
The only hits taken in the service department are by techs when there is a comeback which is fixed on their time.
That's good to know warranty repairs give them revenue, I used to feel bad taking it in during its last mileage.
When you say comebacks , do you mean people coming in claiming a problem that should of been fixed wasn't fixed?
I don't know if I should switch and take my ar to mb of huntington go to rallye and comlain they didn't fix it, because they definitly did not.
Would you feel uncomfortable taking your car that you didn't buy from this dealer and a dealer where you almost bought a car from but walked?
09-14-2011, 10:37 AM
#4
MBWorld Fanatic!
Join Date: Sep 2009
Location: Dix Hills, New York
Posts: 2,108
Likes: 0
Received 7 Likes
on
7 Posts
2012 C250 Coupe
I think there might be some validity to this. I always wondered what the A/C button actually does, because I was always able to get cool air without it on...
Also, I use MB of Huntington now, I wouldn't use them over Rallye. They are lazy and always say (can't replicate problem, or choose not to do anything). I guarantee you that if you brought the problem to them, they would say its normal or something. But heck, you can try if you want. Rallye is much better, I bring my car there when I have a reccuring problem that Huntington doesn't take care of. I would take mine there all the time, but it is considerably further away.
But heck, you never know, try taking it to MB of Huntington, you might get a better service advisor or technician...
Also, I use MB of Huntington now, I wouldn't use them over Rallye. They are lazy and always say (can't replicate problem, or choose not to do anything). I guarantee you that if you brought the problem to them, they would say its normal or something. But heck, you can try if you want. Rallye is much better, I bring my car there when I have a reccuring problem that Huntington doesn't take care of. I would take mine there all the time, but it is considerably further away.
But heck, you never know, try taking it to MB of Huntington, you might get a better service advisor or technician...
Last edited by jctevere; 09-14-2011 at 10:41 AM.
09-14-2011, 11:46 AM
#5
Super Member
A/C button, is it the button in the middle of the temperature dial? I doubt it is for turn off. The dedicated OFF button will turn A/C off but will will turn A/C back on, a toggle button.
I checked "A/C" button function in 2008 C300 manual yesterday. Don't remember very well but it turns on A/C, and re-direct air flow, etc. It doesn't say it will turn A/C off.
I like the A/C "gradually" on and off, unlike the easily noticeable clutched A/C.
I checked "A/C" button function in 2008 C300 manual yesterday. Don't remember very well but it turns on A/C, and re-direct air flow, etc. It doesn't say it will turn A/C off.
I like the A/C "gradually" on and off, unlike the easily noticeable clutched A/C.
Last edited by C300CA; 09-14-2011 at 11:48 AM. Reason: details
09-14-2011, 01:31 PM
#6
Super Member
Thread Starter
I think there might be some validity to this. I always wondered what the A/C button actually does, because I was always able to get cool air without it on...
Also, I use MB of Huntington now, I wouldn't use them over Rallye. They are lazy and always say (can't replicate problem, or choose not to do anything). I guarantee you that if you brought the problem to them, they would say its normal or something. But heck, you can try if you want. Rallye is much better, I bring my car there when I have a reccuring problem that Huntington doesn't take care of. I would take mine there all the time, but it is considerably further away.
But heck, you never know, try taking it to MB of Huntington, you might get a better service advisor or technician...
Also, I use MB of Huntington now, I wouldn't use them over Rallye. They are lazy and always say (can't replicate problem, or choose not to do anything). I guarantee you that if you brought the problem to them, they would say its normal or something. But heck, you can try if you want. Rallye is much better, I bring my car there when I have a reccuring problem that Huntington doesn't take care of. I would take mine there all the time, but it is considerably further away.
But heck, you never know, try taking it to MB of Huntington, you might get a better service advisor or technician...
Nice to hear that about rallye, among other reasons the reason I drove the furthur distance to Rallye (I live in huntington) is because they seemed like a more capable facility. At the same time they didn't fix two of my problems.
09-14-2011, 02:04 PM
#7
MBWorld Fanatic!
Join Date: Dec 2006
Location: Europe
Posts: 6,340
Received 293 Likes
on
245 Posts
223.168 & 213.012 & 906.633 & 214.005
A/C button, is it the button in the middle of the temperature dial? I doubt it is for turn off. The dedicated OFF button will turn A/C off but will will turn A/C back on, a toggle button.
I checked "A/C" button function in 2008 C300 manual yesterday. Don't remember very well but it turns on A/C, and re-direct air flow, etc. It doesn't say it will turn A/C off.
I like the A/C "gradually" on and off, unlike the easily noticeable clutched A/C.
I checked "A/C" button function in 2008 C300 manual yesterday. Don't remember very well but it turns on A/C, and re-direct air flow, etc. It doesn't say it will turn A/C off.
I like the A/C "gradually" on and off, unlike the easily noticeable clutched A/C.
http://www4.mercedes-benz.com/manual...ual_base.shtml
Switching climate control on/off
Important information
When climate control is switched off, the air supply and air circulation are also switched off. Only select this setting briefly. Otherwise, the windows may mist up.
Switch on climate control primarily using the
button. Activating/deactivating
Turn the key to position 2 in the ignition lock.
To switch on: press the
button. The indicator lamp in the
button lights up. Airflow and air distribution are set to automatic mode. or
Press button
. The indicator lamp in the
button goes out. The previously selected settings come into effect again. To switch off: press the
button. The indicator lamp in the
button lights up. Activating/deactivating cooling with air dehumidification
Important information
The cooling with air dehumidification function is only available when the engine is running. The air inside the vehicle is cooled and dehumidified according to the temperature selected.
WARNING
If the "cooling with air dehumidification" function is deactivated, the air inside the vehicle will not be cooled (during warm weather) or dehumidified. The windows could mist up more quickly. This may prevent you from observing the traffic conditions, thereby causing an accident.
Condensation may drip from the underside of the vehicle when THERMOTRONIC is in cooling mode. This is normal and not a sign that there is a malfunction.
The cooling with air dehumidification function uses refrigerant R134a. This coolant does not contain chlorofluorocarbons, and therefore does not damage the ozone layer.
Activating/deactivating
To activate: press the
button. The indicator lamp in the
button lights up. To switch off: press the
button. The indicator lamp in the
button goes out. The cooling with air dehumidification function has a delayed switch-off feature. Problems with the cooling with air dehumidification function
When you press the
button, the indicator lamp in the button flashes three times or remains off. You can no longer switch on the cooling with air dehumidification function. Consult a qualified specialist workshop.
You are correct with the gradual control of the AC compressor, these are clutch-less variable volume compressors.
Trending Topics
09-14-2011, 03:20 PM
#8
Super Member
Thread Starter
I'm telling you you can hear it when the AC compressor goes on and off. Its not the sound of clutches but simply a load and unload on the engine. Open up the hood and stick your head out the door while pressing the buttons, you can hear it.
My dads S550 has a AC off option and within 30 seconds to a minute after you turn it off, you start to feel warm air, not in the C though.
If it is supposed to be like this, fine, and props to Rallye for replacing all these parts for me, one of which included a new fan motor.
09-14-2011, 03:35 PM
#9
Super Member
09-15-2011, 02:34 PM
#10
Super Member
I've never been to rallye but Huntington was hellish for me when I lived in Melville.
Being a repeat customer is a big deal. Im the one who takes both our cars in for service and I have an sa I usually see named kief. Its nice that even when I don't get him he will wave hi and ask what's up. He even notices when im doing a pick up inspection wayyy outside of the service bay and comes over to make sure everything is as asked.
The dealerships and advisors I don't frequent often always seem rushed, annoyed to hear issue after issue, and don't EVER remember small things like hold off on the wash.
Being a repeat customer is a big deal. Im the one who takes both our cars in for service and I have an sa I usually see named kief. Its nice that even when I don't get him he will wave hi and ask what's up. He even notices when im doing a pick up inspection wayyy outside of the service bay and comes over to make sure everything is as asked.
The dealerships and advisors I don't frequent often always seem rushed, annoyed to hear issue after issue, and don't EVER remember small things like hold off on the wash.
01-12-2012, 05:19 PM
#11
Newbie
Join Date: Jan 2012
Location: Ontario Canada
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
W203 c320 Sport Coupe
Any one ever have this problem?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
Many thanks,
Eric
01-12-2012, 05:33 PM
#12
Newbie
Join Date: Jan 2012
Location: Ontario Canada
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
W203 c320 Sport Coupe
In addition, I have a friend currently working for a MB dealership and he confirmed yesterday that my SWITCHING PROBLEM is valid. He tested the AC OFF switch on more than five W203 cars and all can turn off the cooling (taking off the load from the engines). I hope he could find how to rectify the problem soon.
Eric
Eric
01-12-2012, 05:37 PM
#13
Newbie
Join Date: Jan 2012
Location: Ontario Canada
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
W203 c320 Sport Coupe
Any one ever have this problem?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
Eric
01-12-2012, 05:42 PM
#14
Super Member
Thread Starter
I have found that if you press the A/C button to toggle it off, and then turn the climate system off and on, then your compressor is definitely off. I'll just consider it one of my cars quirks, nobodies perfect
01-13-2012, 12:43 PM
#15
MBWorld Fanatic!
Join Date: Nov 2007
Location: NYC
Posts: 2,078
Likes: 0
Received 4 Likes
on
4 Posts
2012 C300 4Matic
Sorry guys, it is 100% NOT a defect.
The AC system has been this way since the W203 facelift and continues on to the 2012 W204. It works like this: when you turn the AC off by pressing the AC button, the compressor remains on for a certain amount of time (dont ask me exactly how long) and then the veins slowly turn the system off - not all at once. And so it usually takes a very long time before the AC actually turns off fully. If you "cheat" by completely turning the climate control off and then back on without the AC, then the unit turns off fully.
This is very stupid engineering rather than a defect. There must be some reasoning that they had in mind when they designed it this way, but it eludes me. They do seem to be VERY concerned about window fogging and this may be part of the reason -- similarly to the recirculate design which causes recirc to turn off every 5 minutes if it is below 40(?) degrees F outside.
It is clear that Mercedes has grappled with this issue for many years - they used to have the "AC OFF" button before they changed it back to being a normal "AC" button. In the E class we had, it was an "EC" button for economy. The reason they continue to flounder with this is because they design the AC system so that the compressor can always turn on whenever dehumidification is required. If you leave the AC "on" it will actually only turn the compressor on if it is needed. For example, in the winter time, if it is dry and cold out and the AC is "on" the compressor will not come on. Should the humidity sensor detect high humidity, the compressor will come on (but only a bit since it is variable!) in order to reduce humidity. If you turn the AC off manually, then the compressor will not kick on even as the humidity goes up and the windows begin to fog. In winter time with AC set to on, you will rarely have to defog your windows manually as the system does a very good job of detecting it (in my 2012 model at least).
The AC system has been this way since the W203 facelift and continues on to the 2012 W204. It works like this: when you turn the AC off by pressing the AC button, the compressor remains on for a certain amount of time (dont ask me exactly how long) and then the veins slowly turn the system off - not all at once. And so it usually takes a very long time before the AC actually turns off fully. If you "cheat" by completely turning the climate control off and then back on without the AC, then the unit turns off fully.
This is very stupid engineering rather than a defect. There must be some reasoning that they had in mind when they designed it this way, but it eludes me. They do seem to be VERY concerned about window fogging and this may be part of the reason -- similarly to the recirculate design which causes recirc to turn off every 5 minutes if it is below 40(?) degrees F outside.
It is clear that Mercedes has grappled with this issue for many years - they used to have the "AC OFF" button before they changed it back to being a normal "AC" button. In the E class we had, it was an "EC" button for economy. The reason they continue to flounder with this is because they design the AC system so that the compressor can always turn on whenever dehumidification is required. If you leave the AC "on" it will actually only turn the compressor on if it is needed. For example, in the winter time, if it is dry and cold out and the AC is "on" the compressor will not come on. Should the humidity sensor detect high humidity, the compressor will come on (but only a bit since it is variable!) in order to reduce humidity. If you turn the AC off manually, then the compressor will not kick on even as the humidity goes up and the windows begin to fog. In winter time with AC set to on, you will rarely have to defog your windows manually as the system does a very good job of detecting it (in my 2012 model at least).
Last edited by acr2001; 01-13-2012 at 12:48 PM.
01-13-2012, 01:03 PM
#16
MBWorld Fanatic!
My W203 does a great job of detecting it, as well. And though it does use swash plate compressor, you can feel the engine load.. not sure why, but I don't really understand the system.
01-13-2012, 11:44 PM
#17
Super Member
Thread Starter
Sorry guys, it is 100% NOT a defect.
The AC system has been this way since the W203 facelift and continues on to the 2012 W204. It works like this: when you turn the AC off by pressing the AC button, the compressor remains on for a certain amount of time (dont ask me exactly how long) and then the veins slowly turn the system off - not all at once. And so it usually takes a very long time before the AC actually turns off fully. If you "cheat" by completely turning the climate control off and then back on without the AC, then the unit turns off fully.
This is very stupid engineering rather than a defect. There must be some reasoning that they had in mind when they designed it this way, but it eludes me. They do seem to be VERY concerned about window fogging and this may be part of the reason -- similarly to the recirculate design which causes recirc to turn off every 5 minutes if it is below 40(?) degrees F outside.
It is clear that Mercedes has grappled with this issue for many years - they used to have the "AC OFF" button before they changed it back to being a normal "AC" button. In the E class we had, it was an "EC" button for economy. The reason they continue to flounder with this is because they design the AC system so that the compressor can always turn on whenever dehumidification is required. If you leave the AC "on" it will actually only turn the compressor on if it is needed. For example, in the winter time, if it is dry and cold out and the AC is "on" the compressor will not come on. Should the humidity sensor detect high humidity, the compressor will come on (but only a bit since it is variable!) in order to reduce humidity. If you turn the AC off manually, then the compressor will not kick on even as the humidity goes up and the windows begin to fog. In winter time with AC set to on, you will rarely have to defog your windows manually as the system does a very good job of detecting it (in my 2012 model at least).
The AC system has been this way since the W203 facelift and continues on to the 2012 W204. It works like this: when you turn the AC off by pressing the AC button, the compressor remains on for a certain amount of time (dont ask me exactly how long) and then the veins slowly turn the system off - not all at once. And so it usually takes a very long time before the AC actually turns off fully. If you "cheat" by completely turning the climate control off and then back on without the AC, then the unit turns off fully.
This is very stupid engineering rather than a defect. There must be some reasoning that they had in mind when they designed it this way, but it eludes me. They do seem to be VERY concerned about window fogging and this may be part of the reason -- similarly to the recirculate design which causes recirc to turn off every 5 minutes if it is below 40(?) degrees F outside.
It is clear that Mercedes has grappled with this issue for many years - they used to have the "AC OFF" button before they changed it back to being a normal "AC" button. In the E class we had, it was an "EC" button for economy. The reason they continue to flounder with this is because they design the AC system so that the compressor can always turn on whenever dehumidification is required. If you leave the AC "on" it will actually only turn the compressor on if it is needed. For example, in the winter time, if it is dry and cold out and the AC is "on" the compressor will not come on. Should the humidity sensor detect high humidity, the compressor will come on (but only a bit since it is variable!) in order to reduce humidity. If you turn the AC off manually, then the compressor will not kick on even as the humidity goes up and the windows begin to fog. In winter time with AC set to on, you will rarely have to defog your windows manually as the system does a very good job of detecting it (in my 2012 model at least).
02-12-2016, 06:14 PM
#18
Newbie
Join Date: Jan 2015
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
CLK A209
Any one ever have this problem?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
If I turn on my climate control system with the AC off, and then press the AC button it goes on, I can hear it kick in at idle with the hood open, however, if I press the AC button to make it go off, it doesn't. It still blows cold air and I don't hear it go off. However, if I turn off the whole climate system, it does goes off as I can hear it, and when I turn the system back on the AC no longer is on. It is annoyying to have to do that to switch from the AC to vent. I took it to Rallye for this and they said it was the heater motor blower that got wet, and they replaced a bunch of parts, but it didn't do anything. And they actually replaced parts, I could see the new ones.
I am thinking of taking it to MB of Huntington, and showing it to them. Do you think they would give me hard time knowing I went to Rallye first and now am there after Rallye claimed they fixed it? Reason I steered clear of Huntington is because we walked out on a deal with them, so I don't trust them with a car that I didnt buy from them, hopefully they don't remeber me.
Also, my out side temp gauge reads too high, Rallye "replaced" the sensor, but its still the same.
Lastly, Ive got a 1000 miles left on my warranty so do you think dealers hate when you take it in last minute and wring out the warranty? I just dont want to **** of the dealers who have my car for a while and can mess with it. I picture them setting soemthing up to fail in the next months after I am out of warranty so I have to pay them for a repair. Do dealers take hits from warranty repairs of does MBusa repay them?
10-22-2018, 12:50 PM
#19
Junior Member
Join Date: Dec 2015
Posts: 18
Likes: 0
Received 0 Likes
on
0 Posts
w168 1998 petrol
2007 w245 here, the A/C does exactly the same. I don't understand if this is intentional or not. As somebody stated the manual tells A/C button will turn the system ON and OFF however it doesn't seem to turn it off until you stop the fans completely,
10-22-2018, 01:36 PM
#20
Junior Member
Yeah, this seems to be how the system is currently set up. Switching off the A/C in our 2011 doesn't turn the compressor off. It seems if the car is turned off, the compressor typically doesn't turn back on. However, I found one day the AC turned itself back on all by itself (switch not illuminated) on a hot day. Car hadn't been driven for days, yet the AC still came on...
10-25-2018, 11:15 AM
#21
MBWorld Fanatic!
And I thought I was crazy ... my car also has the delayed response to turning off the A/C with the button. Cold air comes out for quite some time, then after I quit thinking about it it eventually stops and warm air returns.
It is probably an intentional design characteristic, just different from what most other mfg's do ... just like the trunk lid springing all the way open when you hit the release button. I had never seen that on any car before this one :-)
It is probably an intentional design characteristic, just different from what most other mfg's do ... just like the trunk lid springing all the way open when you hit the release button. I had never seen that on any car before this one :-)
06-04-2021, 07:20 PM
#22
Newbie
Thanks to all for this discussion!
Excuse me for add to an old post and I likely have thr wrong model car to add a comment S211 E500 '04 USA. But, I just experienced same phenomena and it was after a long drive in 90 degree weather. Right or wrong, I often cool the engine a bit before turning off the key after long drive. I started the process during the last few minutes....open windows ... hit A/C but to off and then slowly raise the temp setpoints. Gosh...blew cold a long time and I worried compressor was stuck. It makes sense to me that the system implements a gradual or delayed change. Dont need details as long as no issues. I know this thanks to this thread. It was cute that my internet search led to different threads and arguments about how to properly use climate control etc. Thanks again.
