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I recently purchased a 1994 C280 (my first MB, and there is an unusual problem with the A/C. When I engage the A/C, cold air blows out the middle vent, but it blows luke warm air on the driver's side vent and hot air on the passenger side vent. The easy solution is to keep both side vents closed, but I was wondering if anyone has a suggestion for a more permanent fix.

It is my understanding, from the previous owner, that it is a problem with the actuators. Apparently, each vent has its own actuator to switch between the cold and hot air systems. Is this correct? I would greatly appreciate insights into this problem, as I am new to MB.

Thank you!
 

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[:)] Oh I thought I had been the only one with that problem. Mine is a C 180, 1994 model. I don't know the reason for this faulty A/C but I'm going to have it checked by an A/C specialist this weekend. I'll post the results afterwards. Have you found the cure yet, though?

Do you also get funny smell from the warm air blowing out of the side vents?
 

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1997 C280
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I dont know if it is the same for a 1994 but i have a 1997 and there is only one HVAC acuator for all of the A/C vents. I live in las vegas and in the summer my side vents blow WARM air for the first 10 minutes of the car running. I've been able to make it instantly cold by closing off the middle vent and letting all the air blow through the sides for the beginning of the car run time.[:)]
 

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I have not noticed any foul odor from the side vent blowing hot air. Since I just bought the car last weekend, I am just now begining to understand the problems. Here is what seems to be happening.

1) The middle vents blow cold air all the time when set on the automatic climate controll. This weekend, it was 55 degrees outside and I had the temp guage set for automatic 74, but it continued blowing cold air.

2) The driver's side vent does not blow much at all, although it seems to blow warm air.

3) The pasenger's side vent blows hot air all the time.

My understanding is that it could be a mechanical problem with 'actuators' that act as a valve between the hot air system and the cold air system. Apparently, each vent has its own actuator, so it could be difficult to fix.

Please keep me informed as to the fix and price.

Thanks!
 

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I had this issue and had to replace some sort of control box that was located in the area under the glove box. Give me a day to dig up the old part and Ill give you the part number.
 

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My problem, if its a problem at all, with my a/c is whenever I flip the middle vent louvres up, the side vents will start to blow hot/warm air. And when I pull the louvres back to level, the side vent will go back to blowing cold air, not instantly but gradually. Anyone had this problem?
 

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1994 C280 1996 C36 2002 ML500
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I had a 94 c280 which blew hot air from both side vents at all times. The culprit was the heater valve.
 

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my c280 has this problem mine is not an A/C model just a normal fan/heater. The middle vent is always cold the outers always warm. Anyone know the cure????

help :(
 

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'99 2.3L Kompressor
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Older MBs had some sort of odd behavior like this and it was normal so you will find lots of contradictory posts on this problem in regard to the w202. If you don't have airco, the system may be different and I can't advise you. Usually if it is the duovalve, you will get heat out of both right side (right center and right window) or both left side vents (center left and by the left window). If you get cooled air out of the center right vent but hot out of the right window vent, to me it sounds more like an actuator issue. If it is, god be with you on the journey ahead...

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2011 C300; 1995 C220(sold); 1985 300D Turbo (sold)
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I think the difference between the center vents and side vents is that center vents are connected to outside air, or something like that.
 

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1988 260E (Now my brother's), 1994 C280
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Similar problem on "94 C280

I am having a similar issue, with the side vents blowing hot air and the middle vents blowing cold air. I noticed that when I shut the A/C off I don't hear the noise of the vents closing (I imagined them to be flaps by the noise).
Does anybody have any insight on this? And where would they be located (the "flaps") and how can they be accessed?
Thanks in advance
Raxhi
 
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