Yeah it almost might be cheaper to pay for a flight for jimmy to come down here and help me!!

Welcome to the wonderful world of Auto Climate Control II! That vacuum piece in your picture does control flow to the heater core. You can test it for operation with a Mityvac. If it doesn't move then I believe your servo is sticky, most of them are.

The servo tends to "stick" after some time of non-use. What I recommend to do is to move the temp wheel from cold to hot a few times, waiting inbetween selections for the servo to catch up. Also alternate pressing DEF, AUTO-HI and AUTO-LOW a few times as well.

Also when I went to have my r12 charged last summer the servo system stuck on heat before charging. Following the procedure above and opening/closing that valve in the picture "unstuck" the system for normal operation afterward.

The CCU (Small black box behind glovebox liner) is held on by two screws and a harness. Have you replaced it yet? Any scorch marks on the PCB?

Good grief yall, I fear the CCU-II. :eek: I've never ever in my life messed with one, although I do have an aluminum bodied one out sitting on my work bench. :D
I would first follow what derburger said and see what happens. I would want to know first if that valve you had pictured holds vacuum. If the diaphragm isn't torn then I would do as he says and start switching the setting of the CCU as he described. It sounds like Norm is trying to make cool air, it is just being over-run by heat.
And I only got in Ralph's way and then took his coffee home with me..... :o:o

Okay, I will try to mityvac that valve there tomorrow when I get up. Like I said, the little lever behind it did not move no matter what setting it was on!!! I have also replaced the Amplifier (the little black box behind the glovebox) numerous times, I have three now. No difference with any of them (although the aux water pump burned out, it didn't take out the amp).

Btw I love your tag, I think we need to start a club once mine is fixed!

And as for the sticky servo, I'll try that but believe me I've been moving that dial and pushing those buttons so much it's a wonder they haven't melted yet!

Jimmy, I think you're right (also Tyler said the same thing). I can tell that at various engine temps the heat gets higher or lower in correlation to the engine temps.

You sure do have a lot of ACCII stuff Jimmy, you sure you don't want to take part in the fun?! :D

I don't have a car with ACC-II, so I'll just sell the Aluminum bodied servo and amp that I have at some point. Came off a really clean Euro gasser....

Okay, I dropped off Norm yesterday and I should know by tomorrow or Tuesday exactly what's wrong.

However, before I took it in I did mityvac that pod and it will hold vacuum. However, the vacuum line leading in to it was cracked wide open! So I mityvac'd the pod closed, and took it for a test drive. Still no dice. I was so hopeful that that's what the problem was!

So he's in now, hopefully it'll be something I can fix myself.

Updates Updates....
 

Do we have Updates for this thread ?

He can explain better, but the servo is now working fine, but no AC.:D

more questions
 

I've had my issues with the climate control on my 280SE. It was working well for a time, but now is not quite right. Maybe the readers of this thread can help.

I replaced servo with George Murphy's aluminum unit, along with the amplifier and aux water pump. After the car sat for some time chasing other issues, I found the AC cold and fans working, but no heat. I checked the fuse that brings the servo back to 'park' position- that now works. As does the aux water pump. I've also tested the servo at pins 3 and 5 straight from the battery- I hear the valves open and close as they should.

Now here is the problem. When I measure voltage at the plug side that feeds pins 3 and 5 into the serov unit (ignition on, ACC set to 'DEF') I only get 8 or so volts.

I believe this is not enough to drive the servo, so of course no heat. What could be causing this? A bad amplifier? What feeds these pins- connections from the amplifier or a direct switch from the selector switch on the dash?

jk

Hey guys,

So I'm finally tearing in to my AC system and am at the point where I need to add oil to my compressor and dryer. Actually my compressor appears to be filled already, but I want to drain and refill it for peace of mind (unless that is a bad idea and I should just leave it).

Anywho, where am I able to pick up compressor oil? I can't seem to find it at any of my local autoparts places, and ordering it online seems to be my only option. Does Mercedes carry this at their dealerships?

Also where am I able to rent a vacuum pump from to remove all the moisture from the system? Or am I stuck buying one?

So far I have everything out and have flushed the system, just need to oil the compressor and dryer, tighten everything up, pull vacuum for a bit, and charge it.

And sadly I will be using 134 :/

By the way I did not even have to drain the system before opening it up. I hooked my gauges up and nothing. It was completely empty.

I hope I don't have a leaking evaporator, although I did notice that the o-rings on the dryer were shot. Hopefully the 134 ate through them. Thank god I have replacements.

The local Auto Zoo had a vacuum pump I borrowed by leaving a credit card deposit. If you are going the "vacuum" and "re-fill" route, you might want to perform a complete flush ---- and don't forget to replace the dryer.

^Yep, dryer and expansion valve are being replaced, just need the oil before I can put it in!

I was debating about doing a flush, and I guess I might as well do it while it's taken apart. I'll pick up some cans of it tomorrow when I hit up autozoo. I wonder if they have compressor oil, otherwise I need to draft up $50 worth of parts for Autohauz :D

They also have a flush unit that you can borrow ---- you will need an air compressor to hook up to it.

^Where did you get your compressor oil from?

I believe the "California wine country", napa ?

If you strike out at NAPA try these guys, they've got everything for the HVAC industry:

http://www.johnstonesupply.com/160/SearchResults/tabid/1781/Default.aspx?search=refrigeration%20oil&qty=

For a vacuum pump, try to find an old fridge or small A/C wall unit. If you have a bulk garbage pick up day where you live you can usually find one at the curb. When you find one, cut one of the lines to the compressor. If freon leaks out, pass it up...it's there cause the comp died. If you find one with no freon in the system you've hit the mother load. It's there cause the freon leaked out, but the comp's probably still good. These compressors make excellent vacuum pumps. You can get a fitting at Johnstone that you can solder on the suction side of the comp to connect your gauges to and voila...you've got a vacuum pump. Mine's been going strong for over 10 years now!

Okay I'm in a dire situation!

I uninstalled the old compressor, and when I did the two spacers fell out. Well both are different sizes, and I dont know which one goes where!

I'm just bolting it on dead for now, because I have to drive it tonight. Otherwise all I have to do is pull vacuum and it'll be done!

Klima I (not) Fun
 

Wow ~ no one here knows how to diagnose this wretched old system ? .

I don't have my notes here but it's fairly simple with a Multi-Meter and some bits of wire (I use an old plug from a junker) .

The firewall mounted valve is the ' emergency' by-pass hot water valve, with the engine running press the ' DEF ' (top) button on the CCU and it'll move as the CCU by-passes everything in the entire sytem and pops that valve open and turns the fan on high .

The normal hot water flow and fan controls are controlled by the servo , not the firewall mounted valve .

The servo also controls the various fan speeds .

The passenger side dash vent has low air volume because the flex duct behind the glovebox is loose at one end or the other , you'll see when you have the glovebox out .

The CCU is the dashboard push button unit , the thing behind the glovebox is the amplifier .

learning the correct nomenclature weill avoid you chasing your tail endlessly .

Any Mercedes HVAC system with vertical buttons is the wretched Klima I with the evel servo and DOES NOT HAVE A MONOVALVE .

I have used tested good Klima I amplifiers for $40.00 each delivered .

I have some metal body servos too but I may need one for my TD if and when I find one I like enough to buy... so none for sale just yet .

BTW : once this system is sorted out , it's really good ! heat in winter , 65* F in summer , even in 125* F Death Valley .

^Considering this thread is well over a year old, I have figured out this system more now then I had in my original post.

The flex duct remains open, but the pod holds vacuum.

I have about four different amps for the ac system, including two pulled from working ACCII vehicles. Also I have a CCU which I will replace.

I have waited until this point before going forth with any work, as I now know the system like the back of my hand.

Anyways, a little update about today:

I flushed out everything and created quite the mess. I was able to locate oil from Autozoo and thusly filled the dryer and compressor with it. Taking the compressor off was easy, getting it back on definitely is proving difficult. It would be much easier if it didn't weigh a billion pounds!

Also the o-ring kit I purchased that is 123 specific only has one o-ring that I need two of. Looks like I'll have to go grab some from Autozoo tomorrow. Other then bolting up everything properly, all I have to do is pull vacuum for an hour or two and then charge up the system and see if it works.

If not then I don't know what else to do.

I'm -NOT- An AC Tech
 

But I've been working on it for years and reading the manuals, taking classes & listening to the AC guys etc. .

They all say to only pull 20" or so vacuum for 30 min. to one hour as the water vapor boils quickly under I forget how many inches then it pulls out so you needn't run the vacuum pump for hours like most shops I know do .

Then leave the gauges connected for at least one hour to ensure no leaks before re-charging with your choice of refrigerant .

I'm still using R-12 as it -is- available if you hunt a bit , not too expen$ive either .

I am told the green O-Rings made for Japanese cars will resist R-12 or R-134a and are sold very cheaply by most FLAPS .

I have a kit of various size green O-Rings for the next time I replace a compressor , I'm trying to wait until I have sufficient $ to overhaul the engine first but AC is a must for us old farts and once running , the totally clapped out engine actually runs well and summer is nearly here so.....

^Well that's good to know, I probably would have left it on there for an hour plus.

I am replacing all the o-rings with green ones. However I need two of the same size for the expansion valve which I only got one of. Instead of putting the black one back on, I'll just pick up a generic o-ring kit when I return the flushing tool tomorrow.

Sadly I'll be using 134a. It's easier to get a hold of, and even though my condenser isn't made for it I've had good luck with it in my 190E and it blows cold enough. Cool air of any type is what I'm aiming for right now.

BTW :
 

' Norm ' is *SO* pretty ! .

I'm insanely jealous .

He's the same color as the Euro Spec. Wagon they junked in P-A-P when I was out of State over Christmas , they told me it had been for sale but only got offers of $500.00 so in the rows it went ~ NO RUST , not a speck .

Dagnabit :mad:

I'da happily given them $1,000 for it .

^Thanks! I love the car, I'll never part with it. It definitely is a great looking car, although it does have it's fair share of flaws. Rust being one of them, argh. I've treated most of it, but need to hit the small stuff asap.

It'll get a repaint eventually.

Crap.

Well after finishing up everything today, I went ahead and vacuumed the system and attempted to charge it up. The system took the charge, the compressor works and it's clutch engages, but yet I'm still getting hot air. I have good pressure in the system, everything functions like it should. It almost makes me wonder if all I really had to do was replace the o-rings with the green ones! But it's okay, it needed to be done anyways.

I really think that something is telling the servo to give me heat. I'm going to replace the CCU with one that Jimmy gave me tomorrow, I think that this may solve it. If not, I am either SOL or will have to drop another serious amount of money on a digital servo.

Sigh. :/

Does the low side hose get cold?

So you get hot air or just outside air? The servo valve could be stuck on heat. Turn the key to position # 2 and turn the temp wheel all the way from 85 to 65 or 85 to 65 and get out and listen very closely for the servo changing settings. If you hear nothing tap the servo with your hand.

^Yes, it is cold now. It wasn't before. Also still no aux fan coming on which is weird.

I'll have someone help me do that, but I'm pretty sure that the servo is stuck or my temperature dial is dead. Apparently that happens enough that there are rebuild kits out there for them.

I'll attack it tomorrow.

After you turn the temp dial the servo valve will groan for about 15 seconds.

I have been lucky my servo really hasn't given me much trouble at all, other than when it started leaking coolant about 7 years ago.

Lucky. Mine makes zero noise. What pins could I hook it up to to see if it actually works? This is a rebuilt servo too. I really think the problem lies in the CCU though.

Here are some photos.

http://i435.photobucket.com/albums/q...DSC_0001-4.jpg
Pulling vacuum.

http://i435.photobucket.com/albums/q...DSC_0004-4.jpg
Yep, that here is an empty and dry system. Yehaw.

http://i435.photobucket.com/albums/q...DSC_0009-5.jpg
After sitting for 45 minutes, the system held it's vacuum. That means no leaks, woohoo.

http://i435.photobucket.com/albums/q...DSC_0011-5.jpg
Here is what I replaced. The expansion valve...

http://i435.photobucket.com/albums/q...DSC_0008-5.jpg
The dryer...

http://i435.photobucket.com/albums/q...DSC_0010-5.jpg
And the compressor (under the hoses). As you can see it was hard to take a photo of, imagine how fun it was to actually remove and replace the thing.

Glad I got it out of the way though, it needed to be done. CCU install in the morning.

Im doing this off memory but i think its correct. Use a multimeter on pins 1 and 7 of the AMP, you should see about 5 volts when you turn the temp dial. If you see voltage then you know your amp is good and that your CCU is good and the problem is a stuck servo.

Colin,
If it gets to the point where you think it is Dr. Evil Servo
http://i29.photobucket.com/albums/c2...rEvilServo.jpg
let me know before you order and pay for a digital servo. I have an aluminum bodied servo pigeon-holed in the garage that I grabbed at PNP a while back. It isn't tested but it came from a clean euro W123 gasser. It isn't cracked of course so I imagine it is fine.
We will get Norm working somehow. Sounds like you have the AC side under control, you just need the servo to shutoff the hot water.... {or the CCU to tell it to shut off the hot water}

^Thanks Jimmy, I will for sure let you know.

^^I'll try that in the morning before I tear in to anything major. Do you by any chance know which ports on the servo itself are used to jump it? Like if I wanted to connect power to see if it will turn out of the park position, what pins would I connect it to?

Note I did not install the servo myself, but probably am able to now.

I don't know off hand which pins on the servo you can use to test it. I'll look....

Auxiliary Fan
 

it doesn't come on hadly ever , only when it's seriusly hot out and you're running the AC on MAX for a while , even then it should cycle off again after it cools the condensor down .

Heres a few tests for you:

The terminals are numbered left to right (1-10) as you face the connectors.

Connect +5 volts to terminal 4 and negative to pin terminal 5. You should hear the servo hum. When it stops it is in the "hot" position. (5 volts is best as that is what a properly working amplifier supplies and you don't want to fry it. I have used a small 9v battery in a pinch)

You can test resistance With a VOM on pins 1 & 2, resistance should be 200-250ohms.

To check the amplifier, connect a voltmeter between pins 1 and 7. With the ignition switch in the on position, the voltage should be about a volt. Move the temperature wheel from cold to hot. The voltage should increase to about 5 volts, and when the servo finds it home, the
voltage will drop back to about a volt. If it does not vary, then the amp is bad.

^Awesome, thank you so much Stuart. I'll give that a shot in the morning with all the amps that I have in my possession!

God I love ACCII

Alright Jimmy, might need that servo =[

I'm gonna run to Autozoo to return my vacuum pump, I'll post a detailed reply when I get back.

Servo Testing
 

Take your time , unplug it and do a comprehensive servo test including the use of your Ohmmeter as it has two different travels , one side is heat , the other is cooling and the fan speed wiper contact has two different sets of resistance too .

it is critical that the servo motor travels smoothly (i's quiet but you can hear it) and stops with a 'thump' ~ not slowly tapering to a stop in one direction of travel or the other , this is a common fault and it will cause the amplifier to fry .

There's a bunch of gears , wipers and a threaded screw , all must be 'timed' JUST SO " or it'll (maybe) pass a bench test but foul up on the car .

As the servo is ever so cleverly located in the lowest part of the cooling system , it acts as a sediment trap and the sediment will cause the valves gates to drag or stop and this is when the Bakelite body cracks or the motor's
drive gears strip, etc.

FWIW , ALL auxilliary water pumps have a little white plastic cap on one end you're suppoosed to gently pry out once a year (regardless of use) and drop one or two drops of engine oil in as it is running , this prevents them from siezing up and frying the amplifier (Klima I) or the CCU (Klima II) .

I hope this helps , working methodically and slowly , carefully , will result in ICE COLD AC , just try my old 1980 300CD W/ Klima I :P

The problem that I am having is that the servo is not moving at all. In fact I don't think it is getting any power.

I put my voltage meter on all three of my amps handy, and all of them read the same voltage regardless of where I put the wheel. In fact they all read less then a volt.

I tried connecting power to the servo and got nothing. However it was rather awkward to get wires to the pins, so I'm not totally ruling out the servo just yet.

So here is what I am pointing to right now from all of this: The Servo might okay, but needs to be tested outside of the car. The CCU possibly is not sending the proper signal to the amp and thus nothing is happening. And the amp is dead, all three of them.

I think I'm going to slowly repair the system like I did with the AC components. I'll start with the amp and CCU, then move on to the servo. I don't want to pull the servo until I absolutely have to. Who knows, my amps might just be the problem and my CCU is fine.

vwnate you said you sold amps that actually work correct? I'd be interested in one if it does.

Klima I Testing
 

STOP ! the Evil Servo
(LOVE that picture BTW) is easily tested in the car , it's easiest if you source the electric plugs from a junker but you can also make up some test leads with crimped on ends .

DO NOT even *think* of taking anything apart further than you need to , this is how you'll wind up chasing your tail forever :rolleyes:

You can use battery voltage to run the servo back and forth , remember : it must stop moving with a thunk sound , not slowly load down until it stops moving ! .

I'm in the middle of a serious shytestorm @ work but I will write you a how to test in due time if you need it , it's pretty simple , IIRC George has a nifty booklet he'll snailmail you for free .

yes , I have good used amps but don't buy one until you _know_ the servo is 100 % O.K. ! .

^So just getting some wires with leads and connecting it to the battery should be okay? I was thinking about doing that, but didn't want to fry the servo. I'll give it a shot.

Yes BUT !
 

You cannot just connect voltage willy-nilly and hope you get it right :eek:

It's very important to follow the correct procedure .

Otherwise you'll damage the servo .

Also that servo operates off about 5-6 volts, a full 12V might damage it.

Use alligator clips crimped onto some wire.....

Servo Motor Voltage
 

Yes , the amplifier reduces the voltage but no , 12 VDC directly from your battery won't hurt it.

Obviously , once it stops moving , you don't leave the wires connected and have a beer......

Found another amp in my garage and tested it, it actually varied with the change in the thumbwheel. Here is what I got:

http://i435.photobucket.com/albums/q...DSC_0001-5.jpg
65

http://i435.photobucket.com/albums/q...DSC_0002-5.jpg
75

http://i435.photobucket.com/albums/q...C_0003-6-1.jpg
85

Also I connected power from the battery to the servo and got no response.

OK so it appears that your amp and CCU are working properly, but your servo is not.

Oh joy. Well I guess there is only one thing left to do then.

Paging Jimmy...

Bypass, Bypass, Bypass.

But but but...I'm so close!!!

I might have to for a quick fix.

This is a Mercedes-Benz, not a old Chevy, lets do this the right way.