Have you had the car for a while, or did you just purchase it? Is the temperature different by 5 degrees at all temperature settings or just when you have both at LO?

 

I have the car for over 3 years now. Well you can feel it also a little bit when it's not on LO ( but it's minimal, you'll have to put it on LO to show the temp. diff. to somebody else). In the Netherlands we just don't have many days when it's bloody hot. But when you go on holiday and make long trips with the car in warm and sunny days you'll feel it. I've just noticed it recently. It's not a big issue, but was hoping to find out what the problem was.

 

Is it the volume of air that is different, or the actual temperature.

 

No the volume is the same, only the icey feeling of airco is missing. Left is like a normal car without airco. Right is Airco feeling. I hope you understand what i mean.

 

Assuming that it is not that the temperature control slider needs to be calibrated to match the right side, which is unlikely since it worked fine before, I would suspect it is the temperature sensor that senses the temperature for the left side is faulty and the stepper motor that controls the distribution of air by the heater core is over reacting, opening it too much and mixing too much warm air with the air that flows by the evaperator core (your A/C). The electronic module that reads the information from the sensors and controls the stepper motors is possibly bad, but they are discrete logic and while the dealer has talked me into replacing mine before, it has never ever actually been the problem. Has there been anything work done in the cabin lately. For example, has anyone installed a radar detector, stereo, etc. whereby something could have been done to the temperature sensor. They rarely go bad on there own as well.

The temperature of air that flows through the cabin is primarily controlled by limiting the amount of air that flows by the heater core. The evaperator Core is either on or off...it is either creating 100% cold air or not, depending only on whether the compressor is running or not. And since you have A/C cold on the right side, the only way you can get warm air out is that the air is being drawn by the heater core. The reason for asking if you had a normal voume of air flowing was that if you didn't have much air flowing, then it would be possible that both dampers were shut off...that being the damper for the heater core and the evaperator core. Since you have air flowing, then one of them must be open, and since it isn't hot air, it implies that both dampers are open but that it is getting too much air flowing by the heater core.

I don't have my S430 anymore and don't remember where the sensor is for the left side, but it is very likely that it is faulty.

Hope this helps!

 

Thanks for your work DCSIMMONS!

I'll check it out. If i look at my sensors in the hidden menu (hold REST for 10 seconds then you see the list. It looks like nr. 4 is fluctuating a lot and thats a heater core temp, but on the right side . I've seen on one of the forums that there are 2 in car temp sensors.

Pls check this link http://www.benzworld.org/forums/w220...lp-c-diag.html

But my hidden menu gives me a temp that looks like correct. Could it be that there are some valves not open correct? And therefor airco only goes thru right????

Thank for your help anyway

Bori$

 

If you can locate the temperature sensors, then swap them and see if the right side becomes the one to not work right. If nothing changes then you know it is either the wiring to the temperature sensor or probably the electronic control module that is very unlikely.

The fact that it bounces around quickly suggests that it is an electrical connection since the temperature sensors dieletric mateiral isn't capable of changing it's electrical charastics so quickly.

Don't really have much more for you. Sorry!

 

Ok thanks, i'll work on that. Thanks for your help

 

I have a problem with my S400 (y 2001) a/c system. In warmer day car starts blowing hot air either in right side (more often) and rear or on left side (not rear). This happens typically after ca. 40 min driving. To compensate one needs to move the manual mode and close all other wents except the center consol (temp control needs to set low in failing side). If you stop the engine for ca 5min, a/c works fine about 15min and fails again, but not necessary in same side of the car. Now last couple of days have been below 18 degrees centigrate and system has worked fine. Does someone have a clue, what is the problem?

 

I would normally think that what is happening is that the compressor is kicking off because of to much pressure on the high side...the result of too much freon (or freon and oil) in the system and higher temperature outside. It probably isn't kicking on and off when it is cool out because the pressure on the high side is just below the pressure point.

But I am of the impression that you still have cold air coming out of the middle vents, so if it is cold, then my theory doesn't hold any water. If it is cool, then it is probably the problem because the compressor is kicking on and off, but not enough to get the evaperator coil really cold. You still have cool but not cold air. The next time this happens, pop your hood and see if the compressor is kicking on and off. If it is, then that is likely your problem.

Have you added any freon to the system recently, or more importantly just before the problem started. If you did, then the likelyhood is that you might have added freon with oil to charge the system. The cans of freon come with just freon or freon and oil. Even if you replace a hose or something and completely suck down (stick a vacuum on it), I wouldn't necessarily recommend adding oil. If you replace a compressor, that is a completey different story. Too much oil causes problems though different than not enough.

Since oil won't compress, when you add a can of freon with oil to the system, you will be raising the pressure the system needs to get to to have the same cooling effect. The oil won't compress, and so when a person adds freon to the system, and if they use the test of how cold the air feels coming out the vents to know when they have added enough freon instead of measuring pressure, the system will be over charged. You won't notice it until it gets hot out, and the the pressure on the high side goes high enough that the high pressure switch kicks in, turning of the compressor until the pressure gets low enough. Sitting for 5 minutes cools things down enough that the compressor will run normal until it gets hot enough again that it kicks off. It will then cycle off and on again.

Hope this helps!

 

Center vent is blowing cold air from the side what is not failing normally, after adjusting side failing to LO you still would get a cold air in center vent on failing side also, but not on side vents. Side wents are blowing as hot air the car can give. I am trying to figure the problem out as I bought car recently and I have a 6mth warranty for the car. When car went for fixing, problem did not occur and I am fighting with a dealer to have problem fixed. Now in Holland we are getting a Fall and likehood having hot days before next summer (when warranty is not anymore valid) are getting less likely. Thanks for your comment, but I do not see that as compressor problem as the non failing side works perfectly normal.

 

Does the S400 have a sunsensor? Have you had the hood painted lately, or any work done done in the area of the sunsensor or where sensors are? Just to make sure it isn't a sunsensor, I would disconnect it. It is unlikely, but possible since it has so much control over the A/C.

You mentioned that you were having something fixed. What was it? There is always the possiblity that a temperature sensor got disconnected since the result can be things acting flaky as seems to be the case. If you have cold air in one vent, and warm in the other, then the stepper motor is working and moving for some reason to alter the distribution of air to be from the heater core to the evaporator core. It is unlikely that it is a stepper motor problem since more then one vent or side is effected, and more likley that it is either the electronic control module that controls the stepper motors, or that the electronic control module is getting bad data (temperaturs sensors not communicating with it).
I believe it is probably the latter, and that when they were working on it something go disconnected or broken.

 

I did some test driving today (2.5 hrs). Outside temp 21 C. First 40 min everything worked fine. Then right side started to blow hot air. Around 40 min later everything returned normal. 15 min later left side started to blow hot air. I parked to car for 15 min (engine running) and did sensor reading

03: 72 degree centigrate
04: 18 degree centigrate
05: 2 degree centigrate ( variates between 1.5 to 3)
06: 95 degree centigrate
07: 16.2 Bar
08: 59 degree centigrate

After 15 min standing (engine running)

03: dropped to 9 degree centigrate
04: went up 2 min later tp 72 degree centigrate
05: 2 degree centigrate ( variates between 1.5 to 3)
06: 95 degree centigrate
07: 16.2 Bar
08: 59 degree centigrate (variated during the drive, but readings when A/C failing)

07 was variating while driving between 8.7 to 17.8 Bar

12: seems to work well variating today between 12% to 86%

I drop car a warranty fixing for the A/C problem on Monday, but problem did not occur according the carage when it was there 2 days (temp outside 15.5 degree centigrate and raining).

According to my knowledge car has not been painted.

Thanks for the help.
.

 

hi dc,im new to this,i posted a new question today,chould u have a look at it,ive no heat,very lukewarm airin the left side,frezing on the right,u seem to be a master in this area,id be so greatfull for any advice!! i have a 2000yr s320 myuser name is paulmerc,u can find the question on the s320 forum,thank u

 

I'll do my best to help you out here. I am not a master but you are nice to refer to me in that way.

I do have some ideas for you to start with and maybe I can help you track down the problem.

1st., is your temperatture guage displaying a normal temperature? If it is registering abnormally low, you might have a bad thermostat. If it is moving around on you you may be low on water/anti-freeze and so there isn't enough radiating fluid flowing by the heater core.

You would know if the thermostat was stuck closed because your engine would overheat since the water in the head has no where to circulate, but you wouldn't necessarily know if you had a thermostat stuck open by anything the engine would be doing different other then showing an abnormally low temperatur.

As for what this has to do with why you are getting luke warm air, when the thermostat is stuck open, the water that circulates through the heater core (the interior part that air flows through and provides you warm air) never gets hot and so at best case scenario in the winter you will get luke warm air.

A thermostat is normally closed when the engine is cool, and this keeps the water in the head from being circulated and cooled, helping the engine to come to its best operating temperature as quickly as possible. After the water in the head gets hot enough, the thermostat allows water to circulate thorugh the radiator. This water that is allowed to circulate through the radiator is also the water that would be circulating thorugh the heater core. The thermostat ideally opens and loses very slightly to keep the temperature correct at all times.

If your temperature guage is showing lower then normal, then it is very likely you have a bad thermostat...stuck open...and so the water in the head circulates at all times thorugh the radiator. During the summer you probably wouldn't notice. But with it as cold as it has been, when the cold air flows through the radiator it cools down the water dramatically and so it never get hot.

One way to test for this is to drive down the highway and see if the air coming through the vents gets colder. It is likely that the air will be warmer when you are sittting still sinice no cold air flows through the radiator, and when you are travelling down the road the cold air will cool the water in the heater core providing you with cool air through the vents.

Another possibility is something called an auxiliary water pump. It would be my guess this is actually the problem with the age of your car. It's specific purpose is to flow water through the heater core and if it isn't working, then you will get luke warm air as you are talking about.

It doesn't necessarily explain the cold air on one side and the warm air on the other though.

It is a rather easy item to replace if I recall. To find it look for a small cylindrical motor that is inline with the cooling system just short of leaving just short of leaving the head

Let me know if this helps. There are other possiblities such as stepper motors, climate control modules, etc, but I am guessing your problem is not one of these.

 

electric pump that comes on if the engine is over hot on shut down or when you press the rest button to keep the car heated for up to 30 minutes after shut down in cold weather.It is not a function used during normal operation, the water pump takes care of that.
Run the diagnostics post the numbers run the error diagnostics if your model has that feature. Post the results.

 

hi dc,1st thank u so much for such a quick reply,my mechanic says the termo is ok,but as u say she heats up to norm 90 when parked but when u drive its about 75,i thought because of the weather here in dublin -9, nd she blows colder when driving,ive changed the control unit at ash try and the water pump valve unit at the firewall,the cars reading fault 1269 thats the multi function sencor?/dont know where or what it is nor does the mechanic,do u?someone mentioned sun sencor or the sencor in the car?have to pick up posh relations on dec 26,im dreading it,its -11 tonight!! help me dc?????

 

hi dc,1st thanks so much!! my mechanic says termo ok,but when u start and leave it the temp is 90,when driving its 75,changed heater pump valve at the firewall,changed the controll unit at ash tray,i have 1 fault reading on the unit code 1269,which is the multi control sencors,do u know what or where this is!!evry bodys stuped with this,u c dc i left the car parked up for 8 days when this weather struck,ever since then its not worked,someone said,sunsencor??if u think of anything more let me know,we say in ireland,your a salmon of knoledge,its old irish tale!! thanks again dc

 

hi ohlord,thnks to u also for your reply,u are all so helpfull,the code on the controll panell is 1269,which is error multi function sensors??dont know what or where this is,ive deleted the error but keeps returning when u start the car again,everyones baffeled ,as iv said changed the control unit,water heater valve at the firewall,someone sais termo or sunsor?let the car tick over it reaches 90 but when driving 75 but that still doesnt explain bare lukewarm on the left frezzing on the right side!! any ideas thanks again ohlord,i cannot thank u all enough for ur help!!

 

sorry dc,forget to say i changed the auxilery pump,that was gone!! u say stepper motor or sencors,is there anything i chould try to check thease,cheers again, paul

 

hi dc,just a update from yesterday,this info mite help u and others some time,spent whole day in friend garage regarding no heat in car,we tryed everything and the poss u said,it turns out it was the multi function sencor,its found beside the fuse box on the right as u look into the engine,its the squerish metal ting thats on ur air con vent,itscode is 1269,and on mercs diagrams its called b31/1.hopeits use to u and others sometime,thanks again dc for your help,hope i can return favour sum day,merry xmass

 

Hello,
I recently bought a 2003 s430 and I have the following problem with the climate control.

It will be working fine and then all of a sudden you hear the blower running but you can not feel any air coming out anywhere including when you try to manually adjust the controls for each side. Any help would be greatly appreciated.

Mike

 

Not sure you like it but I had the same problem on my rear aircon. It got fixed by replacing the Duovalve. That part costs £235 + VAT

They had to do some checking though to see if it was something else and that took quite a while (2 hours).

 

 

Hi, i'm new...where in the hell is the "Rest" button..lol? I'm trying to get to the menu..my AC simply does not work..it just blows hot air. It could be a number of things, although, I have been reading these wonderful posts for hours, I think I at least want to start with menu..

thanks.