Understanding W212 Circuits 30,30g,30z,15,15R,87F,87M & 50
If your headlight is a 641/642 Dynamic LED or 631/632 static LED, read here slowly ( post #10) and see the linked post on 641 headlight : https://mbworld.org/forums/e-class-w...ml#post8896407
Last edited by d0nedeal; Dec 24, 2023 at 05:39 AM.
If your headlight is a 641/642 Dynamic LED or 631/632 static LED, read here slowly ( post #10) and see the linked post on 641 headlight : https://mbworld.org/forums/e-class-w...ml#post8896407




.... start your story much back in time please. The day WHEN both headlights were working well.
The rear SAM wing fuses, I can them WING FUSES because they are removeable, the purple plastic cage of fuses 74 to 80 set.... they can be removed from rear SAM as I recall.
Too bad I am not home and can't access my home PC, I tear down rear sam fuse box for re-soldering like 2 years ago. I have lots of photo.
Now , your honest full story line first ......on how your headlight from healthy to be in current "shorted' state ?
Who been in there at the rear SAM ?
Today, can you see that fuse #74 holder both female ports, do they have the copper connector ?
The outside facing female port of fuse #74, is there a wire to it ?
This fuse set purple cage 74 to 80 , one side is to rear SAM using female to male blade, one side is female to wired end. Did someone mess up the wired side ?
I hope my explanation make sense without proper photos




Go to this vin decoder https://www.lastvin.com/ and produce your data card and post it please.
I want to make sure your car has a true 640 series LED and not some modified after market one.
If you ask me question based on non genuine MB components, I can't and wont help you as I do not understand them.
I only know my 641 dynamic LED , genuine MB version, as such my wiring is set up by MB Indonesia to be for 641 headlight.
So get every data true and proper and we can carry on.
.... start your story much back in time please. The day WHEN both headlights were working well.
The rear SAM wing fuses, I can them WING FUSES because they are removeable, the purple plastic cage of fuses 74 to 80 set.... they can be removed from rear SAM as I recall.
Too bad I am not home and can't access my home PC, I tear down rear sam fuse box for re-soldering like 2 years ago. I have lots of photo.
Now , your honest full story line first ......on how your headlight from healthy to be in current "shorted' state ?
Who been in there at the rear SAM ?
Today, can you see that fuse #74 holder both female ports, do they have the copper connector ?
The outside facing female port of fuse #74, is there a wire to it ?
This fuse set purple cage 74 to 80 , one side is to rear SAM using female to male blade, one side is female to wired end. Did someone mess up the wired side ?
I hope my explanation make sense without proper photos
WDDHF8JBXEB008513
Go to this vin decoder https://www.lastvin.com/ and produce your data card and post it please.
I want to make sure your car has a true 640 series LED and not some modified after market one.
If you ask me question based on non genuine MB components, I can't and wont help you as I do not understand them.
I only know my 641 dynamic LED , genuine MB version, as such my wiring is set up by MB Indonesia to be for 641 headlight.
So get every data true and proper and we can carry on.




What does not make sense is you do not have fuse 74 in the slot and yet BOTH headlights we were working back then.
So either something is unique with a 640 headlight fuse system, or someone modified something before.
Untill you see a 640 wiring diagram, we can only speculate.
Maybe someone here can give me a hint for the source of the problems my friend experiences with his W212 220 CDI: completely random, sometimes twice in 100 km, other times once in 1000 km, the car losses power or the engine stops completely and shortly displays various warnings.
The car restarts normally most of the times, but on occasions needs 10-15 minutes before restarting.
Every times those incidents happen, it stores various codes, all indicating electric malfunction (open circuits) of various actuators on the engine bay.
We have checked: engine wirings, connectors, ECU (opened and inspected for cold solderings or damaged components), some of the fuses that feed the engine wiring.
At this moment we are stuck and not really knowing how to proceed.
Thanks
The Best of Mercedes & AMG




Relay J, M, R and N as minimum.
When these relays are semi worn out, they can give lots of funny DTC, because power loss occurred often for short duration.
Temperature sometimes brings effect, colder weather, more issue.
Those relays are at least 10 years old, so its not waste of money even if not all are effected but you renew them.
You also must clean all the ground wires and more so the undocumented WTF ground wire.
Read here : https://mbworld.org/forums/e-class-w...-not-know.html
See the hot relays, that means they will wear out first.
-----------
https://mbworld.org/forums/e-class-w...ving-them.html
https://mbworld.org/forums/e-class-w...ital-wire.html
Good luck............




Maybe someone here can give me a hint for the source of the problems my friend experiences with his W212 220 CDI: completely random, sometimes twice in 100 km, other times once in 1000 km, the car losses power or the engine stops completely and shortly displays various warnings.
The car restarts normally most of the times, but on occasions needs 10-15 minutes before restarting.
Every times those incidents happen, it stores various codes, all indicating electric malfunction (open circuits) of various actuators on the engine bay.
We have checked: engine wirings, connectors, ECU (opened and inspected for cold solderings or damaged components), some of the fuses that feed the engine wiring.
At this moment we are stuck and not really knowing how to proceed.
Thanks
How about identify what common circuit feeds all the faults ???
So many faults....
start high up from feed...
like the MAIN ECU FEED GETTING OXIDIZED...
I am sure we can find something interesting in F-SAM.

Tthat's besides...
+ MAIN STRAP always feeding everything
+ footwell GND POSTS feeding ECU/F-SAM
Last edited by CaliBenzDriver; Aug 7, 2024 at 06:17 PM.
Not sure how it got there or if MB put them there
Anyway, it is now in the glovebox with the other books for the vehicle
Other info is at:
https://fuse-box.info/mercedes-benz
Last edited by Bruce Hubbard; Aug 7, 2024 at 06:59 PM.



