First I did a search and was unable to locate anything on this.

Is there a way to convert the stupid fan control to low, medium, high as opposed to low, auto, High? The auto function is rarely below high and low is often too low. Anyone know of a simple fix?

Chris

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94 E320 with:
18" ///AMG Monoblock II's,AMG Gen II front bumper, H&R spings,500E sway bar, Bilstein sports, Eisemann Exhst, K&N,E500 Headlamps, Crystal Clear Corners, Avantgard Grill ...and more stuff to come! oh yeah 241k miles!!


My Car WOO HOO...... Now SOLD
New car.... 2001 Jaguar XJR!!!!

Excellent question. I just bought a '95 E420 and I have the same issue. Hopefully, someone here will have a helpful suggestion.

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2002 500SL(Black/Black)
1992 300SE(Black/Black)
1992 190E 2.3(White/Navy)
1999 VW Jetta TDI(Pearl Green)
1986 SAAB 900 Base 3 door(White)
1983 Porsche 911SC(Chiffon)
1977 VW Scirocco(DiamondSilver)

How bad do you want one?

I can custom engineer almost anything. The easiest mod would be to use the auto button as a mid speed. Could do more but would require additional control installed.

I can make it as simple send me your Climate control module and in 2 or 3 days I will send back modified version. Or I could send a schematic with a parts list and instructions.


What do ya think? How much is it worth to you.


Anthony Bridges

Anthony!! I dont know exactly whats it worth, ya got me there!! But I wasnt really sure what was involved, I was hoping itwas rather simple but maybe not. What you stated is exactly what Im loooking for though, to make the middle switch a medium fan setting and leaving the other two the way they are. Either way communicate with me here or at badbenz94@yahoo.com.
Thanks!!

Chris

__________________
94 E320 with:
18" ///AMG Monoblock II's,AMG Gen II front bumper, H&R spings,500E sway bar, Bilstein sports, Eisemann Exhst, K&N,E500 Headlamps, Crystal Clear Corners, Avantgard Grill ...and more stuff to come! oh yeah 241k miles!!


My Car WOO HOO...... Now SOLD
New car.... 2001 Jaguar XJR!!!!

I find this a bit frustrating as well... it seems like you have to play with the rheostat wheel to much just to get the right fan speed.

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1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

Yeah, climate control is nice when it works, but when the pushbuttons and thumb wheel get old and start to fail you are left with either no air or jumbo jet noise.

I had some luck resoldering on the pushbutton connections on one unit and getting it to work again but ended up replacing the controller for big $ on my other car.

Regarding the original post (before we got off on a tangent by trying to repeal the First Law of Thermodynamics ), is this a common problem, or a known design issue, with W124 climate controls? My W123 control (rebuilt) seems to do a pretty good job of operating the fan at the appropriate speeds in auto mode. It seems to me that it would be easier to replace the control unit with a rebuilt unit if it's not functioning correctly. If the unit is acting up and causing the fan to run at the wrong speed, attemping to redesign it may just make things worse. Assuming this is not a design problem, it appears that changing the design of a semi-failed component without fixing the underlaying problem is a short term solution at best. Just my 0.002.

What I think that people are missing here is that the auto button is not the "automatic blower control" only. In auto mode the system adjusts the temperature of the heat exchangers as well as the fan speed to obtain the desired setting indicated by the thumbwheel. The further apart the actual and desired temperatures are the higher the fan speed will be. By design once the desired and actual temps are close the blower slows way down. If your climate control doesn't function this way then fixing it will be a lot cheaper and easier than re-engineering some half assed way to make it work like it's not supposed to.

The first thing that I would check is the function of the cabin air temperature sensor located in sunroof/dome light switch. LarryBible suggests holding a small piece of paper (.25" square maybe) up to it to see if it will hold the paper (ie, air being sucked into it)

A non- or malfunctioning cabin air temp sensor would cause your CC unit to do wacky things like blow too much or all the time.

First off I must say that the Mercedes Auto AC is a complicated system that being said it is equally expensive and time consuming to repair. Who really needs "Auto Air" . I WANT AC THAT RESPONDS TO MY NEEDS and not a $500 - $2000.00 repair bill every 2 - 5 years and I’m sure many others don't want that either. I repaired the AC in my benz doing the work myself and spent over $300.00 for parts and hours studing schematics and components. I repaired my BMW AC for less than $100.00 It needed twice as much work due to previous owners neglect but was much easier to repair.

The solution if well thought out can be quite simple. Most AC controls for most vehicles simply turn on a compressor and let you control the blower speed and air mixture.

I typically do not do things "HALF ASS". I have solved many applications for factories and companies all over the world for the past 10 years in factory automation, web control and automated packaging to name a few and have designed and built several machines worth over $500,000.00. I have redesigned many systems for CNC machines that were too complex and too expensive to repair. For example; a failed power supply. 750.00 to replace OE I did it for 29.95 and works just as good if not better with added surge suppression that I incorporated.

I know what I am doing and I always try to think of the best solution for the investment return as well as long term safety and reliability.

I do appreciate your input no matter how negative it might be. I have taken apart my Climate Controller, AC relay used a scope and voltmeter to diagnose my problems and have even reversed engineered the AC relay. I have spent many hours studying the MB Auto AC system and find it too complex for the simple operation it does. It's a "cool" (no pun intended) system and for the MB diehards that want all OE maybe its not for them. But for the others out there that just want their AC to Work, like myself, I think I can come up with a solution.


If I can come up with a simple safe inexpensive solution I believe MB owners will beat a path to my door. It sounds like a challenge to me and I love challenges.

Again thank you again Craig, duxthe1 and skiier3_9 for your posts!

Anthony Bridges

Something like this:

http://catalog.peachparts.com/item.wws?catpk=&sku=227550999

I have a 94 wagon and a 95 sedan. Both have what I believe are fully functional climate control systems. With the high blower setting you get hurricane force winds inside the car, with the low blower setting the air flow is barely noticeable. Auto is a crap shot. I read in the manual that with defrost and auto selected, fan speed is dependent on coolant temperature. Not sure what auto is supposed to do with normal cooling or heating. I suspect that a large temp difference between selected and actual should result in higher fan speed, but the manual doesn't really say. Also, at high outside temperature, recirc is automatically selected. This usually results in higher airflow contributing to the internal hurricane.

Does anybody know how auto is supposed to work?