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I wanna share the information.
All data I gathered took me days to make.
I am sure this can be helpful for any W212 owners.
It all started because when I travel long distance to Bali and stay there for say a month, I do not have access to MB WIS/EPC , which is on my home desktop PC.
So I was thinking : I have to make a simple and A4 print version of all fuses and relays and carry it in the car, for when Uncle Murphy Law decided to dislike me and BLOW my car fuse in places I deemed not safe,
while enroute to Bali or from Bali.... I can sort out which fuse blew and FAST.
As a readiness test too for you guys on Left Hand Drive, go to you Front SAM , don't use any tools at all :
Remove fuse 15,16, 17 and 26 ,27 and 36. Tell me if you can do it without tool assistance ? That fuse 27 will kill your engine as that is ECM power feed for its logic board.
Can you do it ?
For a RHD car : The tough to access fuses due to wiper arm link , are the : 1,2, 3, 18, 19, 20, 28,29,30 & 31. I need to use those plastic fuse puller , sometimes small plier, on each and every fuses at Front SAM.
There is no space for our fingers to pinch the fuse, if no tool/s available. NOTE : On my car I do not get a hard copy from MB Indonesia for the fusess and relay assignment for both front and rear SAM.
You guys in the US , do you get your model specific fuses & relay assignment in hard copy by MB USA ?
Imagine this, you are also on a long distance run and assume you carry back up fuses and relays and tools and 1 important fuse blown on an area with high crime and it is late at night.
How fast can you change that fuse ? How do you ID which fuse is blown ?
So, what I did was :
01. I audit every fuses assigment on Front SAM and F32 Pre Fuse.
With W212 having so much engine variant and country specific variant and options, it is such a time consuming affair to verify all of the 36 fuses at Front SAM. I kid you not.
02. I checked Troublecode/s recorded by car computers when the loss of power by a blown/removed fuse happened.
The types of troublecodes generated and which modules are the ones generating the troublecodes ........here the suprises are plenty.
This test I did, gave me a much better understanding on how the CAN BUS system on our W212 works, very very interesting.
03. I also did a relay failure simulation. Also very interesting result.
Having done the 01 to 03, I then created EASY VIEW of the Front SAM and F32 wiring system which is suitable for use when we are away from home comfort.
Having done all these, naturally I get to be familiar with all the circuits name designation MB uses for W212. The Circuit 30, 30g, 30z, 15, 15R, 87F, 87M and 50.
The super time consuming task were to verify that each and every fuse I have, by diagram ... goes to which component/s on the car and sharing with what other components ?
This task forced me look at the my W212 wirings to an extend I never done before and its really eye opening.
I also became more familiar to the way MB create its Front SAM wiring diagram. It is not the most easy to understand wiring diaghram.
The amount of data on Front SAM wiring from all possible options, left or right hand drive version, which engines are used, special market like USA and Canad etc, certain cut off dates and many more.
So much more of the time spent to only ID what options/module my car DOES NOT have instead of what my car have... LOL.
I also learnt how a low sales volume engine and short sales period ( 2 years ) for my 3.0 TT is a very tricky engine to gets its data on the WIS. Buried too deep.
The link betweens diaghrams to diaghrams sometime lands me to the common M276 3.5 NA version while WIS/EPC should actually know by VIN that I am on M276.8 3.0 TT engine. Very frustrating.
I have attached the information I will be printing and placing in my car, so it is specific to my car only.
While it may share many similarities with other W212 models, you have to make your own version to be accurate to the dot.
I am sharing my original files, you can edit as needed. I also am sharing MB documents to assist those wanting to make the same kind of file like mine.
If you want to really see to the level of details where and what each fuse power is heading to, one will need the WIS/EPC.
If you read thru slowly, you will realized the documents I made can assist you even for general electrical based troubleshooting at home.
Its like a note book for me, pages of reminders on how my car is wired by MB.
For now it is F32 and Front SAM only.
Next few weeks I will explore the Rear SAM.
Happy reading..............
Will continue....
I add more documents at 2nd post in an hour or so, Engine ECM and Front SAM.
MB forum is laggy at the moment for attachment.
Wow....damn, my 3rd world country MB is like an outcast .
I did not get that fuses print like yours.
Thanks Cali
Attached, Rear SAM sheet 5 which is where N118 Fuel Pump Control Unit is at. Fuse F42 20 amps for your M276 3.5L NA engine and if after June 2010 date of built.
M157 engine N118 will be at sheet 4 and fuse F89 30 amps.
Also attached the N118 fuel pump diaghram. All you need to see is cordinate K2 at the diaghram for M276 3.5L NA.
The rest of the other 3 fuses shown there feeding N118 are for other engine models, ignore them.
This is why you will need to get the eBay knock off version EPC/WIS if you dont have it yet, MB wiring is so full of engine options,
removing what is NOT for our engine will take more time than finding what IS for our engine
Considering your need to run A/C year round your engine fan is heavily taxed... it may be interesting to study the diagram of FAN control module to see how ECU controls speed with a PWM line, 100Amp feed from PREFUSE & GND and signaling pinouts...
I believe the fan takes the spot as the largest onboard consumer.
Perhaps we can get to understand why it sometimes blows its Prefuse link.
I am not too worried about blowing the Fuse 154 at F32 serving this possibly up to 800 watts, or 67 amps at 12 volts, speed control efficiency loss say 10% and 75 amps at maximum speed.
This site explain how the engine ECM* N3/10 ( *pin 18 at connector F ) of our M276 3.0 or 3.5 pumps out the PMW duty cycle. https://w220.wiki/WIS_20.40_Fan,_Fan_Clutch
I am more worried of the fan itself failing and then blew fuse 154 at F32.
Based on HVAC pipe insulation test, you seen I have recorded blown air temperature from radiator at 88C.
Imagine the fan speed control unit at the lower left side of fan cowling ( some older models ) and/or the electronics inside the middle/motor ( most newer models ) of the fan itself has at least 88C ambient temperature to work at and plus
all heat generated for its own working = a real hell of a job for the electronics of fan unit M4/7.
If its not too tough, perhaps opening up the fan motor to check the circuit boards like below video would be under "preventive" maintenance
This fan speed controller is inside the motor
it looks like the fan controller is now built-in the $600 fan unit with a low repairability factor.
The video shows aged solderings as the cause of failure: lead-free solder, vibrations, high heat, high current spikes...
The look of the circuit board is consistent with a 3-phase speed control, such as the LPP besides here the windings feeds are nicely kept ultra-short to produce less electrical noise.
The wiring harness has a one-way control by PWM for speed request plus Key-ON to wake up the module.
I wonder how the ECU figures when the fan is failing besides radiator temps shooting up towards head gasket territory? The work of this fan is really essential for the engine longevity.
Perhaps the later W212 featurr a more advanced version with a two-way LIN signaling between the Fan-ECU.
Can you source the FAN-ECU wiring diagram to find out if GND post is shared or separate from right side headlight??
As far as preventive maintenance, the old fan in the video was designed to be non-repairable.
The only thing to do is minimize internal heat production from the internal electronics with a decent alternator voltage and a good GND.
Also consider the fan wiring connector is subject to water intrusion... seal wires and seams with engine RTV prior to crusties growing from always-ON direct power source !!
+++++++
Q: What can cause FAN to blow 100A Prefuse?
High current from low voltage and dried out bearings?
Last edited by CaliBenzDriver; 09-08-2021 at 12:28 PM.
There is not enough information on how the thermal management for cooling fan works. Surely it responds to thermostat and HVAC demand.
All I know is that it has activation + speed trigger by Engine Computer pin 18 at connector F, which is labeled LUES meaning Engine Fan PWM signal.
F22 fuse from Front SAM feeds power to the logic side of M4/7. The power side gets that big 10mm wire from MR4 of F32, that 100 amps fuse.
There is no better detail information or diagram on how M4/7 internal works. Same as all other "modules", they are drawn as a dotted box, shown to us only the connecting wires go to which pin/terminal.
However this PWM signal from Engine Computer is a simple one I am sure, 10%, 25%,50%,75% and 100% Duty , that's all.
More like old fashion home ceiling fan speed controller with 4 speed using capacitor, but instead PWM signal now.
The fan motor itself must be also a 3 phase speed control capable to deliver what Engine Computer or HVAC wants, but the real power/speed controller is at the fan itself also using PWM.
I don't think there is any reporting of what RPM achieved by the fan. In theory if the fan blades are not damage, the combined 3 phase PMW pulses will equal to the fan RPM.
I think if fuse 22 blown while engine running, fan will go top speed. But many sensors for engine will go blind too.
If this information from https://w220.wiki/WIS_20.40_Fan,_Fan_Clutch is correct :
Zero RPM requires engine computer to send 12V for 10 miilisecond per every interval of 95ms. The 25%, 50%,75% speed....I don't know, the 90% is explained as a signal opposite of 0%, below :
If (only) I have a bi-directional scanner which can command cooling fan speed , perhaps part of the regular maintenance is to measure how many amps a known healthy/good fan is at 10% and at 100%.
Its a bit of hassle to lift up F32 housing and measure amperage at MR4 cable output, but it won't take too long. Maybe do the check once a year and from there hopefully the amps reading log can show
if any obvious amperage increase over time occurs. Most constant operating motors for pumps at industrial level, many check it this way + thermal imaging for its bearing and coils.
For my 3.0 TT and I believe will be similar to 3.5 NA, Fuse 22 serves these engine sensors too :
FOR OTHER THAN ENGINE : Cooling Fan 650 or 800 watt, its integrated control M4/7 only
IF FOR ENGINE. Fuse no 22. 15amps for Z7/36 & Z7/36z1 circuit 87 M2e connector sleeve, feeding :
- Purge control valve (Y58/1)
- Coolant circulation pump relay (K60)
- Left bypass air switchover valve (Y101/1)
- Right bypass air switchover valve (Y101/2)
- Boost pressure control transducer (Y31/5)
- Coolant Thermostat Heating Element ( R48)
- Left oxygen sensor heater downstream of CAT (G3/5r1) , so this is Bank 2 sensor 2.
- Right oxygen sensor heater downstream of CAT (G3/6r1) , so this is Bank 1 sensor 2.
- Right oxygen sensor heater upstream of CAT (G3/4r1) , so this is Bank 1 sensor 1.
- Left oxygen sensor heater upstream of CAT (G3/3r1) , so this is Bank 2 sensor 1.
- Right bypass air switchover valve (Y101/2)
- Engine oil pump valve ( Y130 )
If I remember correctly, a low freon charge can also trigger cooling fan full blast ...yes ? Maybe not for W212 with 3.0 TT, but for some other engine version...I don't know.
Some great info, thanks for sharing. About the OEM fuse booklet, when new they are stored in the spare tire well, that is where I found mine. I decided to keep it with the owners manual, in the glove box.
Well , my market for E400 is very low volume and right hand drive.
I guess MB Indonesia simply dont want the trouble to do a fuse table print out rather accurate to my car.
I am guessing the US market one, its fuse list as you described at spare tire, is really accurate and not as generic as the EPC/WIS Front SAM fuse assignment...yes ?
Well , my market for E400 is very low volume and right hand drive.
I guess MB Indonesia simply dont want the trouble to do a fuse table print out rather accurate to my car.
I am guessing the US market one, its fuse list as you described at spare tire, is really accurate and not as generic as the EPC/WIS Front SAM fuse assignment...yes ?
What would be your idea for repair, if Fuse 22 keeps blowing up?
I've asked "https://mbworld.org/forums/w212-amg/762284-e63-limp-mode.html" and no one has an idea. I believe my car's (fuse 22, front SAM) and your car's have great similarities.
You stated in the W212 AMG section : My mechanic unplugged every connection that has fault codes, and fuse 22 still keeps blowing... As soon as he connects the ECU the fuse 22 blows. He went on vacation, when he comes back he'll try disconnecting the ignition coils as well. He has an idea about it. Will keep you all posted.
I am sorry to say but when I read : when he comes back he'll try disconnecting the ignition coils as well. I think you better get a more qualified mechanic.
Fuse 22 does not feed any ignition coils, not even in M278/M157 engines. I do not know which engine is yours among the 2 of the V-8 I mentioned.
Let me save you time and frustration and hopefully prevention of parts cannon spending spree
Quiz him, tell him to write down all components fed by Fuse 22. I will verify it for you.
Show me what codes are reported by the scanner ?
I am very bothered when I read this : My mechanic unplugged every connection that hasfault codes
Fuse 22 supplies power to X,YZ etc etc.
Powerloss to a component or part of a module may not always be registered as FAULT CODES, because sometimes that part of a module itself looses power and can't register any fault.
Fault registration only is possible if a system is awake/alive or half-awake* ( *because more than 1 fuses supplying power to it ) or by a neighbouring module on the same CAN line.
The proper way is :Your mechanic is to unplug every connection at the devices/sensors,fed by Fuse 22,as per diaghram N10/1 Front SAM Sheet 3 of 10 and as per N3/10 engine computer (ECU) for your specific engine and including
the wiring harness out of N10/1 Front SAM to N3/10 engine computer if required so, just in case the is a short circuit at wiring assy.
This is not including yet, the possibility of the ECU itself is faulty, touch wood.
For now the comforting information is, Fuse 22 is only blown WHEN and IF ECU is connected , this is a comfort to know that wiring harness from N10/1 Front SAM is very much probably OK.
I am attaching N10/1 sheet 3 , my JPEG easy view version to trace the connection to M278/M157 ECU wiring diagram.
Also what I believe as ECU wiring diagram for your engine M278/M157. See the fine print on these documents lower side and verify that indeed that is for your ECU.
MB WIS diaghram is NOT FRIENDLY, if your mechanic uses AllData or Mitchell version of MB wiring, I suggest don't.... use MB WIS orginal wiring diagram.
Mitchell-DIY I got it, it is CRAP !!! Lots of error .
So vacuum pump was leaking part #A2762300265 and the Shutoff Valve was damaged so the coolant did the short (At Rear Left Cylinder Head) part #A2782000831, it totally cooked it.
Pictures of shutoff valve
I still need to order parts, test again for short. I hope the problems stop here. And I hope someone finds this useful.
So the parts have arrived but the SHUT-OFF-VALVE part #A2782000831 is no longer made, and the part has been updated to part #A2782002152 Called FEED LINE. It's a totally different looking part.
So there's no electrical connection, like with the old one. The question is what to do with the cable that goes in (old part). So I've found out you need part #A0025457383.
Good news is, everything got a lot cheaper. Bad news is, I need to wait some additional time for the cap. Hope it goes all well in the end. 35Days already w/o my car haha
Damn, this component of yours is also my FEAR #1, same function in my car just different shape and no electrical control...but same shietty plastic.
I plan to change it in 2023 late or early 2024 or 10 years car age.
Damn, this component of yours is also my FEAR #1, same function in my car just different shape and no electrical control...but same shietty plastic.
I plan to change it in 2023 late or early 2024 or 10 years car age.
The car is fixed! If you replace Old #A2782000831 with New #A2782002152, all you need is #A0025457383, for the dongle cable that basically goes nowhere anymore. There are no codes, no errors, no chkeng.
Hey my headlights stopped working ran a scan it said I have an open /short circuit on circuit 30? Can’t manage to find out which fuse number is that? Can anyone help please
Hey my headlights stopped working ran a scan it said I have an open /short circuit on circuit 30? Can’t manage to find out which fuse number is that? Can anyone help please
Depending on model year and headlight code 6xx, the power can come from fuse 29 and fuse 30 of front sam or fuse 74 and 75 of rear SAM.
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
08-03-2021, 10:19 AM
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haha
