S-Class (W221) 2007-2013: S 320 CDI, S 350, S 450, S 500, S 550, S 420 CDI, S 600

Pre fuse box under the bonnet F32/3

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Old Jan 28, 2026 | 09:08 AM
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Pre fuse box under the bonnet F32/3

these stupid cars have 5 different pre-fuse boxes all claiming to fit !!!

my car has thrown the red alternator light last few months - key on off - tends to get it to decide there is nothing wrong, or sometimes rev it up and it goes away - and using the silly hidden menu for the volts it seems perfectly OK.
14.2volt most of the time then you slow in traffic and at 500 rpm idle it drops to 13.9v

however when your back is turned a few seconds later it drops to 13.1v and as you pull away by 1200 rpm like clockwork it pings back to 14.2v or more - as if its being commanded to work like that
now most likely the alternator is old and tired and it needs the brush pack - but that looks like a horrible job I can't be arsed to do....

and this latest episode after 3 months standing with an always on charger connected - Note: it was correctly disconnected at time of start up...
red battery light comes on in centre of cluster and stays ON - 30 seconds after start up
stuck my diagnostics on it and I get
the ignition switch EZS error (and have often for the last year - but nothing ever played up and it always clears and stays gone for a few weeks)
the engine that always clears and has no symptoms and always stays gone
then these never noticed previously
902B terminal 61 implausible
9022 coupling relay F32K1 control line short circuit
key on off it got over itself
and a drive 2 hrs later also stayed gone

so the ignition switch has a software update available - plus a rather secret 2021 update available nearly all Mercs have outstanding - making me think they go caught yet again with hooky software we need to dispose of
the engine is likely confusion with whatever is throwing the fun
but the relay F32/K1 I don't think can be anything to do with the alternator - and it turns out this Relay is an irreplaceable unit of the front pre fuse box alongside the battery....

not really thinking about diagnosing properly I was wondering why this was playing up and remembered its not just the simple box of nothing it looks like - and all the circuit boards likely don't like the bath they get when trying to make the screen drains function using the jet washer !!!!

so I decide I'll pull it off clean up inside and see what’s happening.... but whilst I can get a nasty secondhand one easily for equiv of 40 to 70 USD (they do play up and likely all older and more decrepit than the one I have !) - then looking about I find a guy selling a brand new one round the corner for a equiv $100 - now quite likely they have blown it up playing about on stuff they have no idea about - and are just trying to recover a few pennies - however all set to give it a go at the price - when I double checked - it turns out these mad cars have different pre fuse boxed based on vehicle spec / engine type...

his was an A 221 540 0850 with 3 connector terminals next to each other beside the fuses and then there's another A221 540 0750 where its alternate terminals as per below
parts docs didn't help - popped 2 miles to my local dealer - and yep I need the one ending 0750 - only ONE in the country - should turn up tomorrow for £130
I hate pulling cars apart without having something else to test against and or fit when you realise its fubar'd




Last edited by BOTUS; Jan 28, 2026 at 11:54 AM.
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Old Jan 29, 2026 | 04:06 AM
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Part has showed up - texted me at 08:01 to say come and get it

Yesterday had a chat with the old boy in the Merc parts about the world falling apart - (he's worked in Merc parts industry for 44 years) and was meant to retire, but he's back
He said to me don't you get bored doing nothing.... I would sit in a cafe - everyday the kids came out of school and just ransacked the place, it was like clockwork - Plod do absolutely nothing - and last week they stabbed one of the kids to death
And yet somehow in US 60% are supporting the Soros funded rioting in Minnesota....

you couldn't make it up

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Old Jan 29, 2026 | 01:56 PM
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So that was a waste of money - its just a box of air and a few hidden fuses

The 9022 Coupling Relay fault is likely the gunk from the appalling design - that allows water ingress to collect in the three bottom connectors and corrode the wiring / sockets unseen
The box does not split taking off the top as it appears - you split it in half the other way see pics
The Relay is replaceable
What I presume is a Capacitor is soldered on, but if you can get this would be easy to swap
The new pre fuse box was made in 2024 so its 18 years newer
I suggest any of you that want less aggro - pop these bottom connectors off ASAP and check, clean add ACF50 to these stupid plugs and sockets - note whenever you open the bonnet rain spills directly on this box - I guess ending up by design, right where the corrosion is
ALL these Pics are from my 20 year old box



















Last edited by BOTUS; Jan 29, 2026 at 01:59 PM.
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Old Jan 29, 2026 | 02:07 PM
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I see they even fitted the Relay upside down - so it can fill with water and never drains
Note the case is not even close to being anything like water tight....

CROOKS !!!
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Old Jan 30, 2026 | 08:18 AM
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oh - and I didn't even get the clip on fuse box lid in the box !!!!
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Old Jan 31, 2026 | 09:17 AM
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Originally Posted by BOTUS
oh - and I didn't even get the clip on fuse box lid in the box !!!!
If it's got a separate part number then it's a separate part, so not sure why that comes as a surprise...🤷
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Old Jan 31, 2026 | 10:11 AM
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Political demonstrations are not the result of funding, but people who are displeased and under represented. Who else would brave the cold to demonstrate against a heavy handed paramilitary police force?

George Soros does not always get credit for his humanitarian work. His politics are liberal, which was not always a sin, back when liberals and conservatives worked together to actually solve problems, rather than make false charges and claims against each other. But that was over 40 years ago.

From AI Search:

George Soros funds a vast network of philanthropic organizations, primarily the Open Society Foundations (OSF), which he has endowed with over $32 billion to support democracy, human rights, justice, and education globally, with significant funding for progressive causes, racial justice, and governance reform in over 120 countries. His funding also extends to political advocacy through groups like Democracy PAC, supporting liberal causes and candidates, alongside impact investing via the Soros Economic Development Fund (SEDF) and initiatives like the Open Society University Network (OSUN).
Key Funding Areas & Initiatives
  • Open Society Foundations (OSF):
    The main vehicle for his philanthropy, supporting democratic transitions, rule of law, health, education, and combating authoritarianism.
  • Racial & Criminal Justice:
    Significant investments in Black-led racial justice groups and criminal justice reform, including a major $220 million commitment.
  • Higher Education:
    Funding universities worldwide through OSF and the Open Society University Network (OSUN) for research and education.
  • Political Advocacy:
    Donates to liberal and progressive political groups and super PACs, such as Democracy PAC, to influence elections and policy.
  • Economic Development:
    The Soros Economic Development Fund (SEDF) uses patient capital for social impact, investing in emerging markets.
  • Early Philanthropy:
    Began by funding educational exchanges in communist Hungary in the 1980s and scholarships for Black South Africans under apartheid.

Scale & Reach
  • Over $32 Billion: donated to his foundations.
  • $23 Billion: in endowment assets for OSF.
  • Active in 120+ Countries, supporting thousands of grants annually
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Old Jan 31, 2026 | 10:52 AM
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Originally Posted by smiles201
Political demonstrations are not the result of funding, but people who are displeased and under represented. Who else would brave the cold to demonstrate against a heavy handed paramilitary police force?

George Soros does not always get credit for his humanitarian work. His politics are liberal, which was not always a sin, back when liberals and conservatives worked together to actually solve problems, rather than make false charges and claims against each other. But that was over 40 years ago.

From AI Search:

George Soros funds a vast network of philanthropic organizations, primarily the Open Society Foundations (OSF), which he has endowed with over $32 billion to support democracy, human rights, justice, and education globally, with significant funding for progressive causes, racial justice, and governance reform in over 120 countries. His funding also extends to political advocacy through groups like Democracy PAC, supporting liberal causes and candidates, alongside impact investing via the Soros Economic Development Fund (SEDF) and initiatives like the Open Society University Network (OSUN).
Key Funding Areas & Initiatives
  • Open Society Foundations (OSF):
    The main vehicle for his philanthropy, supporting democratic transitions, rule of law, health, education, and combating authoritarianism.
  • Racial & Criminal Justice:
    Significant investments in Black-led racial justice groups and criminal justice reform, including a major $220 million commitment.
  • Higher Education:
    Funding universities worldwide through OSF and the Open Society University Network (OSUN) for research and education.
  • Political Advocacy:
    Donates to liberal and progressive political groups and super PACs, such as Democracy PAC, to influence elections and policy.
  • Economic Development:
    The Soros Economic Development Fund (SEDF) uses patient capital for social impact, investing in emerging markets.
  • Early Philanthropy:
    Began by funding educational exchanges in communist Hungary in the 1980s and scholarships for Black South Africans under apartheid.

Scale & Reach
  • Over $32 Billion: donated to his foundations.
  • $23 Billion: in endowment assets for OSF.
  • Active in 120+ Countries, supporting thousands of grants annually
This far, ICE have expelled less people than Obama. But because Trump set their mandate, they must be evil incarnate🤦

And unlike pseudo philanthropists such as Soros or Gates, at least Trump was duly elected. Twice.

Not sure what that has to do with a pre fusebox on a twenty year old car though🤔
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Old Jan 31, 2026 | 11:03 AM
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ABSOLUTELY AND MAKE SURE YOU GET AN OEM ALTERNATOR
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Old Feb 1, 2026 | 04:35 AM
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the NGO effect is to ensure funding to provide better capabilities to the "rioters" - more able to unsettle and irritate the police with fake legal arguments so the agro jumps up a gear faster, they can better equip and coordinate to last weeks not hours, and of course to come across better for the lying media - and when we really want insurrection the college funded scum have payback and do their duty on the streets...

it ensures this minnesota style rubbish has been going on in hundreds of countries across the world for 50 years delivering the deep state agenda - check Ukraine 2014, you can trace the current 10 million deaths after 4 years of fake madness all the way to that one guy

its "was" all part of the plan - until donald unset the apple cart - a particular group of "germans" and a number of royal families are not amused - through a rather clever slight of hand the US have spent the last 100 years entirely funding and enabling their take over of the world, and turning most of in to a sewer just as they want

its spun in the last 12 years so far, these families now want to do a deal with China and Russia against the US.... as if those two super powers will ever let the European filth pull that one off after 800 years of stabbing them in the back
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Old Feb 3, 2026 | 10:39 PM
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Check your ZGW. Just disconnect/reconnect the harness to it. If you have loose pins disconnecting/reconnecting can move them and change your problems. Fix then is to get new ZGW and have Ninja code it for you or solder your old ZGW pins like I did.
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Old Feb 4, 2026 | 03:46 AM
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I missed typing a bit of the 9022 Coupling Relay error code

its really "Coupling Relay Battery" - as this car has the early twin battery setup, I think the corroded connection to the middle bottom connector meant the car wasn't able to see both batteries correctly and so threw the Red battery cluster light
will see if it remains over its hissy fit...
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Old Feb 4, 2026 | 04:13 AM
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The greened or oxidized pin inside the connector may have the electrical crimped wires " eaten " inside the PVC insulation, so it may look good after cleaning but without a good conductivity.
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Old Feb 4, 2026 | 06:47 AM
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I don't think it was bad - car seems OK at present (famous last words and all that),
I had some better pics I just reviewed and enlarged - looks like I got it just in time - the point was to remind all others with the early ones to pop them off and fill sockets with ACF50 - that stuff is like magic - designed to stop corrosion on aircraft skins and works great on electrics



Last edited by BOTUS; Feb 4, 2026 at 06:52 AM.
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Old Feb 4, 2026 | 06:50 AM
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I am sure that will stop corrosion from now on, but I am referring to the corrosion already done,
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Old Feb 4, 2026 | 07:02 AM
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if never used ACF50 its strange stuff it seems to eat corrosion already there - it makes plastic come back looking like new too

https://s3-ap-southeast-2.amazonaws....A4_17.2.20.pdf
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Old Feb 4, 2026 | 07:18 AM
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Sure, eat corrosion meaning that the part corroded remains without. the part that was corroded and the corroded part is the one we miss.

Anyway, if everything is ok is all that matters
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Old Feb 14, 2026 | 04:34 AM
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Originally Posted by Arrie
Check your ZGW. Just disconnect/reconnect the harness to it. If you have loose pins disconnecting/reconnecting can move them and change your problems. Fix then is to get new ZGW and have Ninja code it for you or solder your old ZGW pins like I did.

silly light was back on this morning....

I have had issues connecting xentry to this car since forever - always says far lower volts than the batteries state (which is normal - but not as low as the socket claims)
then was fiddling with his e class and I remembered I have NEVER had connection issues on his (VCI was even saying different things and his gets 13.9 at the socket mine usually says 13.7 (both using same big boy battery support) when the battery is at 14.5V so now I'm going to get these CGW links soldered to see if it behaves

oddly after a short run and a restart the battery icon goes away and the assist message clears too....

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Old Feb 14, 2026 | 05:48 AM
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Originally Posted by BOTUS
silly light was back on this morning....

I have had issues connecting xentry to this car since forever - always says far lower volts than the batteries state (which is normal - but not as low as the socket claims)
then was fiddling with his e class and I remembered I have NEVER had connection issues on his (VCI was even saying different things and his gets 13.9 at the socket mine usually says 13.7 (both using same big boy battery support) when the battery is at 14.5V so now I'm going to get these CGW links soldered to see if it behaves

oddly after a short run and a restart the battery icon goes away and the assist message clears too....
I would change this pin before checking the water ingress at CGW,


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