Over-Engineered Climate Control

[Squiggle Dog]

Seriously. I have the dashboard out in my 1979 300SD and am looking at all the crap that comprises the climate control system; wires, tubes, vacuum do-dads, sniffers, chips, servos, switches, etc. It looks like spaghetti under there. I'm sorry, but I am used to 1950s American cars that have a lever for heat, a lever for the blower motor, and a vent flap.

I am seriously considering ripping out all this junk and just fabricating my own manual controls to fit inside that square zebrano wood panel. Probably a cable to open and close the heater valve, maybe a rheostat for the blower motor speeds, and a cable to open the vent flaps. And then put the AC switch up above it (it will fit) in place of where the sunroof switch is now after it becomes a manual sunroof.

Right now I have heat (already ripped out the evil servo unit and replaced it with a valve and a flush tee) and the fan works at high speed when I press the defrost button. All I want is full heat or no heat, blower on or off (multiple speeds would be nice), AC with the press of a button, and control of the defroster flaps. All it takes is some cables, a rheostat, and a switch. Simple is good.

I have some left over manual climate control parts from a Euro 1977 450SE I parted out. I was just going to install this, but I don't know if I have all the parts I need (or could find/recognize them anyway). I also noticed that there is a simpler version of this with only one rheostat. In fact, there was a 1977 280SE at the wrecking yard with the simple manual controls and I was going to pull the whole assembly today, but the car already got crushed.

I probably can't afford a complete manual climate control assembly, so I am just going to make my own. Heck with these complicated power accessories. This car is getting manual windows and a sunroof as well. I'd do away with the air conditioning if I didn't think I was moving to Kuwait in a few months. I'll probably keep the automatic transmission since it's such a pain/expensive to convert to a stick. Besides, I have a rebuilt spare transmission just in case and I like being able to put the car in gear and forget about it.

This is more of a rant than anything. It just disgusts me that a car company can take something as simple as heater controls and make it so ridiculously complicated. But don't worry, I still love you, Mercedes-Benz!

[compress ignite]

X2

The first space shuttle was less complicated (Maybe the newer ones are,still)

[GaryF]

Originally Posted by Squiggle Dog

It just disgusts me that a car company can take something as simple as heater controls and make it so ridiculously complicated. But don't worry, I still love you, Mercedes-Benz!

I think Mercedes were getting ahead of themselves, trying to load the car with technology before it was invented. Just look at the 600 limo with hydraulic trunk opening and closing. At least most of the stuff in modern cars is software rather than hardware...I mean they dont even connect the peddle to the throttle mechanically anymore.

[alabbasi]

Originally Posted by Squiggle Dog

I'd do away with the air conditioning if I didn't think I was moving to Kuwait in a few months.

You're planning to take the SD with you? I would wait until I got there and find a vintage MB. Most of the custom versions and hot models like Lorinsers, AMG Chameleon etc were exported to the middle east by the Sheiks with chique.

Furthermore, old cars are as cheap as chips there. You could probably score yourself a bargain

[todds]

Well I'm not sure I would agree that the American cars were simple when it came to this stuff. The climate controls on my 67 Mercedes are about as simple as it gets, basically as you described: A cable to operate the heat, and a switch for the fan essentially. Any optional a/c was aftermarket hang-on as stock and weren't much more than on/off. In comparison my 67 Caddies both had the same ridiculous mess of vacuum hoses/valves/servos/etc that you describe with your later S-class. There was even a combination vacuum valve/sensor device in the coolant hose which would not engage the blower if it was too cold when first started in the winter and turn off flow when the a/c was on, just like a present day system. The servo was a ridiculous affair with something like 8 different vacuum lines running in and out of it and one big one on the side. Plus there was the "coffee can". Heck, my rear suspension air levelling even got the air pressure from a big aluminum compressor pump powered solely by engine vacuum, very weird. The amount of electric contacts to go bad in that car was just plain silly, whenever you changed a setting on the a/c, you were changing vacuum, electrical contacts, and a rheostat all at once. I used to boggle at the wiring diagrams. The one thing that was bombproof with the caddy's a/c was the compressor, it was a huge long axial 6-cylinder model that could probably cool my whole apartment. Road-hugging weight!

All this stuff drove me nuts and was never working 100%, in my opinion the simplicity of the contemporary Mercedes in these aspects makes it a more rewarding car. The late 70's is another story, but I don't think the American cars were any different then either.

[ctaylor738]

Don't forget that the servo unit actually came from Chrysler, and was first used on the Imperials.

Personally, I've gotten a good deal of satisfaction out of figuring out these older systems and making them work properly. But to each his own.

[Squiggle Dog]

I am loyal to my cars, so I would probably take both of them over with me to Kuwait (I hope I can buy biodiesel there). It may be hard to find 300SDs over there since they were an American-only car (let alone in the brown I like). Also, my 1967 turbo diesel fintail is a one-of-a-kind.

True, not all 1950s cars were simple. Cadillacs were among the more complex of these cars. And my 1967 fintail is nice and simple.

I will be glad when my climate control is bye-bye and manual-ized.

[Oracle12345]

todays cars are the most complicated things out there, more complicated than spaceships and other things.

[ja17]

Hello,

I suspect the early climate controls were added to the USA bound models to satisfy the American appetite for gadgets. All the european models had very nice simple and easy to understand manual controls for years while all the complex climate controls were shipped in the USA bound cars. Find a nice euro model in a scrap yard and get the system out of it if you like manual controls.

Mercedes did not even have the dash switches and levers labeled until USA regulations required it in the late 60s. Looking at the row of six or seven unlabeled and identical switches on a 190SL dash is about as simple as it can get once you memorize what they are!

Yes early AC and climate control parts were made here in Ohio by Ranco. The expensive servo units were shipped from here to Germany and then back to you after a major price adjustment! Your local Napa store sold them for the Chrysler at a much better price.

Most good designs start off being simple and do not work very well. The next generation evolve into something that works but is very complex. Eventually, if they evolve to the last step, they become simple again and work better than ever.

AC systems, emission control systems, and climate control systems on early MB cars were after-engineered for the American market. These were weak points on these early cars. Let's face it, we could not even get cup holders from Mercedes for over 100 years!

[wbain5280]

Someone, on the tech help forum I believe, took the control unit from a Cavilier, and fit it into an MB. It looked pretty good as well.

[Mark DiSilvestro]

Originally Posted by wbain5280

Someone, on the tech help forum I believe, took the control unit from a Cavilier, and fit it into an MB. It looked pretty good as well.

By the late '70s, most American cars used a vacuum system, even on manual syatems, to operate the various vent modes. So if one can figure out the exact plumbing arrangement required to operate all the vacuum vent servos on an SD, I can see the possibility of adapting the heater/AC controls from something like an '80s Chevy Cavalier.

With my '84 300D, I got around this issue by getting a Euro model with manual heat/AC, as used in the 240D.

Happy Motoring, Mark

[230/8]

Squiggle:

Get out the tape measure, figure your available space and then check in with the folks at Vintage Air. They can make anything fit and have compact heat/AC systems off the shelf.

http://www.vintageair.com/

230/8

[Squiggle Dog]

Thanks for the tips.

[280EZRider]

Originally Posted by ctaylor738

Don't forget that the servo unit actually came from Chrysler, and was first used on the Imperials.

That's right. And they probably got that idea from their earlier disaster - an auto transmission that had push-buttons for gear selection mounted on the dash, left of the steering wheel. We used to call this "Typewriter drive."

[mercmad6.3]

Originally Posted by 280EZRider

That's right. And they probably got that idea from their earlier disaster - an auto transmission that had push-buttons for gear selection mounted on the dash, left of the steering wheel. We used to call this abortion "Typewriter drive."

My favorite shifter was the type writer. But you only used D and R and N to start so they never wore much and when they did it was only on the trans end. But in my 426 63 Fury it would freak other drivers when I went past them and they could see me punch D with the rear tyres smoking....

The Variuos workshop CD's have a good section on how to sort out which Vacuum canister is not working and in most cases it's not the air which has failed but the heater valve on the firewall letting hot water past when it should be stopping it.
And why move to to a toilet like Kuwait apart from the obviuos($$$$$$$$$$$$)? .
Once there you will find life insanely boring so I can understand the need to take your own toys. But as others have mentioned there a tons of flasshy cars and many are considered worthless by ther indolent locals. I had a picture recently of a NEW AMG 63 CLS abandoned on the side of the road in Kuwait.
The locals don't think much of old cars,those that are over 2 years old,they prefer this..