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  #1  
Old 05-09-2011, 04:53 PM
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Live ACC footage...

http://www.youtube.com/watch?v=Ol5zxgtarB4

This is an old leaking servo that I opened up. I'm manipulating the temp wheel in the car which moves the servo motor. The actual electronic part of the servo isn't that complicated. Just the servo motor and a little pot that provides motor position info to the processor.

Someone PLEASE correct me if I'm wrong but isn't a servo motor just a motor that can have the shaft position accurately controlled? I understand that a "Stepper" motor has the position feedback built in.

The rest of the inside of the servo isn't that much different from a regular multi function switch with a multi function vacuum switch in there as well...

I have another video of some troubleshooting that I've done with the ACC.

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  #2  
Old 05-09-2011, 06:42 PM
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It's not often you get to see Satan's heart at work.
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  #3  
Old 05-09-2011, 07:50 PM
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http://www.youtube.com/watch?v=UBpNvtWGG4w

This is where I am now. I took the top off my servo and bypassed the vacuum control part. There is a position that you can place it in that keeps all the flaps working properly. It seems like if I let the servo control it it gets screwy which I believe are vacuum leaks where the rubber disc meets the aluminum plate.

I need to check the auxilliary pump fuse because it doesn't seem to be working.

I still need to check out the problem with it not shutting off It's tied into the AC but I can't seem to figure it out...
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  #4  
Old 05-09-2011, 08:38 PM
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you have a vacuum leak somewhere, do you have a might vac?
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Old 05-09-2011, 08:49 PM
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check both sections of the defrost pod and the green-yellow vacuum line.
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  #6  
Old 05-09-2011, 09:05 PM
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I have a mighty vac but i'm in the process of separating what circuit does what. I guess I'm going to start with the circuits coming off the main brake booster line. I did find that one of the check valves was a little weak. It wasn't terrible but it didn't seal 100%.

Now, where to find replacement check valves...
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Old 05-09-2011, 09:16 PM
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Originally Posted by 79Mercy View Post
check both sections of the defrost pod and the green-yellow vacuum line.
Is the defrost pod the one in the center at the top?

Thanks for the help guys!
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  #8  
Old 05-10-2011, 09:20 PM
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This thing is about to whip my @ss

All seems well so far but I still have a vacuum leak I can't seem to pinpoint.

I took the servo apart most of the way and cleaned/lubed the gears and motor. It sure sounds a lot smoother. It kind of "groaned" before. It's not leaking under pressure and the valve is working well. The thumbwheel actually changes it from heat to cool with no problems!

I also removed the blower relay and fixed the contacts inside.

Now the trouble...

I can start the engine and wait for vacuum to build up, place it on Hi-Cool and it works OK for a couple of minutes. It then slowly changes from center vents to defrost (Like vacuum is bleeding down) then runs for about a minute with the AC blowing out the defrost vents and then there's a click behind the glove box and it stops.

I thought it may be the automatic control switching it off but I drove it around a bit and it never came back on. Turning on "defrost" gets it running again and I can switch to "hi-Cool" and it flips to center vents for a few minutes and stops

I'm considering calibrating the thumbwheel, plugging the recirc pot (Can I just plug both hoses without screwing anything up? When I unhook the vacuum lines with the ac running it kills the whole thing.) and I'm about to try to hunt down the leak.

I also replaced the "sniffer" hose with some pipe insulation.

Any advise would be most welcome!

I did put the mity vac on all 3 of the branches from the brake booster line. The 2 that go into the car seem to hold pressure well. (One had vacuum on it with the engine running! It was pulling a vacuum FROM the inside of the car which I thought was strange...

I also replaced one of the check valves at the main trunk because one seemed a little weak.

The only line that didn't hold vacuum was the one that runs to the back of the IP and branches down under the car.

I've also found several hard plastic lines that are just open and I can't find out where they go. The ends aren't discolored so it appears they have NEVER been hooked up.

Friggin' green wire is weird as well With stuff like that from the factory how are you supposed to troubleshoot it
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  #9  
Old 05-11-2011, 12:11 AM
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Quote:
Originally Posted by newtodiesel View Post
you have a vacuum leak somewhere, do you have a might vac?
Where did you get those tires????
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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership
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  #10  
Old 05-11-2011, 12:18 AM
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Quote:
Originally Posted by 1980sd View Post
Now the trouble...

I can start the engine and wait for vacuum to build up, place it on Hi-Cool and it works OK for a couple of minutes. It then slowly changes from center vents to defrost (Like vacuum is bleeding down) then runs for about a minute with the AC blowing out the defrost vents and then there's a click behind the glove box and it stops
You have a blower relay behind the glovebox and it is controlled (to some extent) by a vacuum switch. That's the only thing there that will click.

You really must follow the test protocols in the ACC II FSM. You will need to check all of the pins on the test connector to ensure they are all within specification.

The in-car temp sensor must be tested, the temp wheel resistance values, etc.

The vacuum system is actually quite easy to test, when following the FSM.

You apply vacuum to a specific hose and if it doesn't hold vacuum, the FSM tells you what to look for and which part is in that circuit.

You really do need to follow that vacuum test procedure....Robert
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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership
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  #11  
Old 05-11-2011, 12:21 AM
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Quote:
Originally Posted by 1980sd View Post
Friggin' green wire is weird as well With stuff like that from the factory how are you supposed to troubleshoot it
The 116 (and some others) used a section of electrical wire (often green) that acted as a controlled bleed. I have seen many people take these out from under the dash and discard them, or use them to make repairs.

You should have NO open connections.
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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership
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  #12  
Old 05-11-2011, 02:03 AM
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Quote:
Originally Posted by Doktor Bert View Post

You should have NO open connections.

I have 2 open connections from the servo into the cabin under the dash. They are the small diameter hard tubing. One black,one white. I can't find ANYTHING near by that they could be disconnected from. The ends aren't discolored like some of the other tubes either so It doesn't look like they were EVER hooked to anything. They are just there in the bundle.

They mock me...

I did check the big "double" pot under the blower and one side didn't hold vacuum. I plugged both hoses and it didn't seem to change anything. The pink pot holds vacuum.

I guess I really need a FSM. I've been trying to fumble through it with the diagrams.

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