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One of the BW Old Guard/R129, W204 Moderator
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Discussion Starter #1
Call for resources, if available. The manuals I have, ie the MB CD and the online manual, as well as the printed volume 1 and 2, are so poor in quality that I cannot follow the wiring traces (or read the wiring color codes, numbers, etc) on the diagrams. Also, the manual seems to be lacking in a good component location descriptive for items such a FPR, DEF, and other relays, and even states the def relay is "...in the cabin, behind the dash, to the left of the steering wheel...' This would be true on a right-hand drive, but that is not indicated.

The info for the later cars, ie 560, are of very good quality.

Very Frustrating...

Anyone have access to better quality wiring diagrams of climate control system, and the entire car as well?

Thanks
 

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Call for resources, if available. The manuals I have, ie the MB CD and the online manual, as well as the printed volume 1 and 2, are so poor in quality that I cannot follow the wiring traces (or read the wiring color codes, numbers, etc) on the diagrams. Also, the manual seems to be lacking in a good component location descriptive for items such a FPR, DEF, and other relays, and even states the def relay is "...in the cabin, behind the dash, to the left of the steering wheel...' This would be true on a right-hand drive, but that is not indicated.

The info for the later cars, ie 560, are of very good quality.

Very Frustrating...

Anyone have access to better quality wiring diagrams of climate control system, and the entire car as well?

Thanks
This is just an example. But if it looks good enough I will go find the right ones.

 

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One of the BW Old Guard/R129, W204 Moderator
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7,143 Posts
Discussion Starter #3
Thanks, but the printed manual I have does have fairly readable schematics. Sorry to state otherwise above, but no component location guide that I can find anywhere in the vol 1 or 2 of the service manuals exist. Been so long since I got them down from teh shelf... Cumbersome, but I can make-do.

I am chasing a problem with the ACCII system on the '78 I am helping with. Vacuum good, master switch 19 working, blower functional (when "hot-wired"), all fuses good, servo good...

Everything buttoned up correctly and... NO BLOWER ON ANY SETTING!

I have the fan plug off the servo controller, and I have put 12V on one of the fan terminals (medium speed, but did not note which terminal number) to get the blower to work. What I have now is a fully-functional system, except no fan speed control. In DEF, I get HOT air thru def vents as designed, center vents (and floor vents) are closed. In Bi-Level, the pods switch over correctly, but the temp wheel seems not to respond as the servo drives to the cool side (water off)regardless of the temp wheel setting, and the air comes from the floor and then center vents (slowly switches over from floor to center as the air temp cools). Appearances are the system thinks the interior of the car is warm enough, and drives the servo to turn off the water. In auto high or low, the air comes from the center vents (of course the fan speed does not change) as designed, but is cool only.

In summary, Def is hot, all other functions drive the servo to what appears to be the park position, and only ambient cool air comes thru the selected vents. If I disconnect the fan wire and replug the fan plugs onto the servo, I can make the servo transit from hot to cool with the temp wheel, but NO FAN!

Also, the aux water pump runs "sometimes", seeming to be only when the engine is cold, but above 40C. After engine warms up, I have not seen the water pump run.

This is driving me crazy... I am gonna have to take a break from this one. At least the owner can get warm/hot air from the def as I have it hooked up now (and a little from the floor gets thru in Def setting, probably from bad seals).

Of course, the dash end vents work, but I didn't mention them in the diatribe above for obvious reasons...

This is a poorly-maintained 1978 450 that the present owner has had for a few years. He bought it with problems, and only now has he found a "sucker" willing to help him resurrect it. We have removed the seats and re-padded them. rebuilt the WUR and verified plumbing, cleaned the tank, the FD, and all lines. Had the injectors pop-tested, and verified fuel pressures. Car is running 95% satisfactory, but still needs a little tuning. Adjusted the HT lock-downs to mount correctly, overhauled the top latching system (the levers on top release and cable adjustment), adjusted the soft-top cover to close properly, fixed the loose AC controls in the dash, and various other items. Been successful so far, but ACCII has us stymied. IF servo were bad, I'd put in Unwired Tools kit, but no need in this case.
 

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I got the wiring diagram and unit location sheet from the LA Classic Center for my 75. Took it to Kinko's and had it blown up to 24" x 36". No more magnifying glass. Actually I do that with any component I will be working on. May be my imagination but the drawings in my 1978 manual seem to be much clearer than my 83.
 

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One of the BW Old Guard/R129, W204 Moderator
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Discussion Starter #6

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I actually took some of the diagrams and put them in to photoshop, adjusted the contrast, put them together, then blew them up. Sort of stinks that you have to do this. I've look at the Mitchell diagrams for this car, and they are not that much better either.
 

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Thanks, but the printed manual I have does have fairly readable schematics. Sorry to state otherwise above, but no component location guide that I can find anywhere in the vol 1 or 2 of the service manuals exist. Been so long since I got them down from teh shelf... Cumbersome, but I can make-do.

I am chasing a problem with the ACCII system on the '78 I am helping with. Vacuum good, master switch 19 working, blower functional (when "hot-wired"), all fuses good, servo good...

Everything buttoned up correctly and... NO BLOWER ON ANY SETTING!

I have the fan plug off the servo controller, and I have put 12V on one of the fan terminals (medium speed, but did not note which terminal number) to get the blower to work. What I have now is a fully-functional system, except no fan speed control. In DEF, I get HOT air thru def vents as designed, center vents (and floor vents) are closed. In Bi-Level, the pods switch over correctly, but the temp wheel seems not to respond as the servo drives to the cool side (water off)regardless of the temp wheel setting, and the air comes from the floor and then center vents (slowly switches over from floor to center as the air temp cools). Appearances are the system thinks the interior of the car is warm enough, and drives the servo to turn off the water. In auto high or low, the air comes from the center vents (of course the fan speed does not change) as designed, but is cool only.

In summary, Def is hot, all other functions drive the servo to what appears to be the park position, and only ambient cool air comes thru the selected vents. If I disconnect the fan wire and replug the fan plugs onto the servo, I can make the servo transit from hot to cool with the temp wheel, but NO FAN!

Also, the aux water pump runs "sometimes", seeming to be only when the engine is cold, but above 40C. After engine warms up, I have not seen the water pump run.

This is driving me crazy... I am gonna have to take a break from this one. At least the owner can get warm/hot air from the def as I have it hooked up now (and a little from the floor gets thru in Def setting, probably from bad seals).

Of course, the dash end vents work, but I didn't mention them in the diatribe above for obvious reasons...

This is a poorly-maintained 1978 450 that the present owner has had for a few years. He bought it with problems, and only now has he found a "sucker" willing to help him resurrect it. We have removed the seats and re-padded them. rebuilt the WUR and verified plumbing, cleaned the tank, the FD, and all lines. Had the injectors pop-tested, and verified fuel pressures. Car is running 95% satisfactory, but still needs a little tuning. Adjusted the HT lock-downs to mount correctly, overhauled the top latching system (the levers on top release and cable adjustment), adjusted the soft-top cover to close properly, fixed the loose AC controls in the dash, and various other items. Been successful so far, but ACCII has us stymied. IF servo were bad, I'd put in Unwired Tools kit, but no need in this case.
I know that this is an old thread, but thought I'd give is a try. Got an ACCII problem and thought you might be able to make a suggestion or two. The problem is a current drain (.36 amp) that drains the battery in about 3 days. After lots of searching, I disconnected the plug to the Aux water pump (also called the heating water pump I believe) and the current drain stopped. I finally found a readable electrical diagram and I find two switches in the circuit. One is a vacuum operated switch (Refrigerant Compressor) and the other is a thermal switch (Temperature Switch for Heating Water Pump). Do you know anywhere I can find the physical location of these switches. I will replace both if necessary. In the mean time I will leave the plug off.
Any suggestions are appreciated.

Thanks
JC201
79 450SL
 
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