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1994 E320 Sedan
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Discussion Starter · #1 · (Edited)
Hi everyone,

Long time, no post. :) I've been lurking still, just went quiet, because my W124 had been so trouble free for so long. That winning streak has come to a close. Something to do with the aux fan circuit got that fuse so hot, that it melted the fuse box:



The broken fuse was done by me, when I still thought "oh maybe I can still save it!" :laugh So now, I'm trying to buy a Genuine MB replacement, and that's where the confusion lies.

This is the part number stamped onto the original box: 1245402050



That part number isn't shown on parts.com, although I did find it on the MB of South Atlanta site.

When I searched MB of South Atlanta by year/make/model, I turned up 1245401750. Unlike *2050, this one does show up on parts.com.

A separate google search, using something generic like "w124 fuse box part number," turned up 1245401250.

And finally, even stranger, my original fuse box has a sticker on it, with a part number 1244407806. When I look this one up, it shows up as an "inboard cable harness & belt warning device."



My instinct tells me to order 1245402050, which is what came originally on the car. Does that seem reasonable? Or would I be better off going to the dealer this time, and letting them figure it out?

Incidentally, I've replaced the fan resistor as a part of this process. The last time I tested it, it was fine, but when I looked under it, it looked like the resistors/capacitors/whatever they are leaked something out. I believe it was original to the car, too, so no harm putting in a new one. They're cheap enough.

I'd sure appreciate any guidance. Thanks!

P.S.: Helpful tip. When these fuse boxes melt, the fumes smell remarkably like diesel exhaust. When I smelled the smell, I thought for sure it was a truck next to me in traffic. :)
 

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'01-E320 & 02-ST2
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Seeing as you're in the US, I'd load up the EPC, plug in your VIN, and then see what the newest part number for your fuse box is. MB shows superseded parts that way and then you'll know if one of the other numbers is the correct replacement or for a different model/features.

Subscribing to the EPC is free, but you do have to use a windows OS. ;)

EPC-net Online

Good luck.
 

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1988 "Zender" 300CE Coupe, 2009 Renault Koleos, 2007 Kia Rio Sport
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Found it on a EURO site you old lurker KR !!!
About $40 US + shipping

Its called a SICHERUNGSDOSE 31,45 € + shipping
 

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1994 E320 Sedan
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611 Posts
Discussion Starter · #4 ·
Found it on a EURO site you old lurker KR !!!
About $40 US + shipping

Its called a SICHERUNGSDOSE 31,45 € + shipping
Ha! I'd gotten so used to the 124 being perfect that I stopped reading up. I also got into my 99 Miata. It had a lot of needs when I bought it, but is really nice now. I even had a set of Bilsteins custom valved by a stock car shop near Mooresville.

I ended up buying the same part number that came in the car, the one ending in 20. It showed up at the dealer in Raleigh for $68 all in using my MBCA discount. Wired it in tonight. What. Huge pain in the butt! I dunno if many of you have seen the back of this fuse box. The wires connect into threaded fittings, with a ring terminal in the en pd of each wire. It's actually very nice wiring. Anyway, the connections are kind of in a stair step configurations such that once you have a row done, the next row is blocked by the work you just finished.

I ran out of energy to transfer the fuses over and start the car, but I did finish the wiring. :)
 

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1994 E320 Sedan
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Discussion Starter · #5 ·
Things are not as good as I had hoped. Something involving the number 6 fuse (horn and turn signals) is inop. I thought I had it licked, but I'd tested using the hazards. Turns out those are on fuse 9.

Any suggestions for how to proceed? The connection is clean and tight. This stuff all worked fine before I replaced the fuse box, so it's got to be something to do with that job.

Is it possible that the wiring for #6 (which is purple with a black tracer, if memory serves) runs from the bottom of the fuse box, into one of those relays near the firewall? With the amount of tugging I inevitably had to do to move the wires from one fuse box to another, I'm wondering out loud if maybe I pulled something loose on the relay side. Is that a possibility?

Thanks in advance. Mostly I'm trying to narrow things down before I go after it with a test light and a voltmeter.
 

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money pits of various forms
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FWIW I have the same problem with my 87, melted aux fan fuse. Following this thread.

Also, I have a similar problem with my horn and turn signals. I ended up isolating the horn away from the turn signals. Inop or blowing fuses?
 

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1994 E320 Sedan
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Discussion Starter · #7 ·
FWIW I have the same problem with my 87, melted aux fan fuse. Following this thread.

Also, I have a similar problem with my horn and turn signals. I ended up isolating the horn away from the turn signals. Inop or blowing fuses?
Inop. All worked fine before I replaced the fuse box.

By the way, that is NOT a job you want to do if you can avoid it, so don't let that fuse melting take the entire box out. It's a tedious and awful job. From my experience, it can also introduce new, exciting problems that didn't exist before.

What made the job painful is that the back of the fuse box is in sort of a stair step configuration, much like the actual fuses are. That meant that by connecting wire number 6 for example, the one directly behind it is now obscured by 6. This makes it difficult to get a screwdriver onto the lower one. And the more wires you've got connected, the worse the problem gets, especially farther down the box, toward the back of the car and the low-numbered fuses.

Here's the original one and the new one side by side:



Almost done:



All wires have been transferred. I had been doing one wire at a time, so I didn't lose my place. Because of the access problems I mentioned with not being able to get a screwdriver on some of them, I ended up having to take some off in order to finish other ones. That's the reason for the green tape labels I made. They say things like "behind 6" or "middle of back row."

 

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1993 400E
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Sorry I didn't see this sooner.

You didn't need to replace the fuse box.

There's a service bulletin on this.

You install an aux fuse holder and use a 30 amp strip fuse

I'll see if I can find it, my 93 400E came with it, so I have 2

One for the blower, the other for the aux fans
 

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1994 E320 Sedan
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Discussion Starter · #9 · (Edited)
Sorry I didn't see this sooner.

You didn't need to replace the fuse box.
Oh no!

There's a service bulletin on this.

You install an aux fuse holder and use a 30 amp strip fuse

I'll see if I can find it, my 93 400E came with it, so I have 2

One for the blower, the other for the aux fans
Thanks for the info, Clark. I've been chasing problems with the aux fan circuit since I bought this car in 2011. The connection in that fuse slot was dodgy when I bought it, I cleaned it up, and it behaved fine for a while. You and I were talking about aux fan problems on this car about a year ago. When we left off, you suspected something wrong with the pushbutton unit for the HVAC. Then Thanksgiving came, then Christmas, then my daughter was born, and I'd forgotten about it.

I'll table the aux fan issue for now, and try to at least get the car back to the same state as it was before I did this. :) Everything worked fine before, and now the horn and turn signals (fuse #6 ) are inop. I feel like at some point last night, I had them working correctly, but perhaps not.

The connection labeled "6" is tight and rock solid. What I can't quite figure out is, what's the other side of that fuse connected to? Maybe I've got another screw loose (lol) elsewhere, which is somehow connected to 6.

Otherwise, does#6 go back to one of the relays in the relay box? With all the inevitable moving around of those wires when I was transferring from old to new, I wonder if maybe I pulled something loose from the back side of those relays, the parts that the pins plug into.

I'm still pleasantly surprised at how much of the car still works. :) But I'm a bit annoyed that something that used to work, doesn't, and that's clearly something I've done wrong.
 

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Discussion Starter · #10 ·

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Discussion Starter · #11 ·
Fixed! :)

Incredibly, the screw holding the two ring terminals onto fuse position 6 was STILL loose. Only by taking off the wire in front of it could I get it tight enough. Strictly speaking, I took 6 off too, inspected it, and even pulled it out of the fuse box end of the wiring jumble, to see if I could figure out where it goes. I, uh...couldn't really see very far into there. :confused: So I reseated the convenience relay, and reconnected 6, and the one in front of it.

Winmutt, I wish I had good news for you, but I don't. What I can see is that at the fuse box, two ring terminals eventually lead to three individual black/violet wires. I couldn't see where they went, although in fairness, I did NOT pull out the relay assembly. I wanted to try the easy things first, and I guess I got lucky.

Clark, in case you don't find it, would any dealer have awareness of the service bulletin, and the parts needed to put in the strip fuse? I think my car already has a strip fuse in place for the HVAC blower. It's on the driver side shock tower, under a little black plastic cover.

In the meantime, I can offer this experience for the rest of our W124 folks: don't replace the fuse box unless you absolutely have to. It's kind of a pain in the butt. :)
 

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1994 E320 Sedan
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Discussion Starter · #14 ·
They all came this way from the factory. :laugh
Yeah, I thought that was the case. But it's always looked like an afterthought, cosmetically, to my eye.

After spending two weeks driving my Miata around town, with its loud exhaust, lousy (factory original) seats and revalved Bilstein shocks, the W124 is like coming home to a nice comfy bed. What a wonderful car to drive around...when its electrical system isn't setting itself on fire. :)
 

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1997 s320, 1994 E320 Cab, 1989 300ce (parting out soon)
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Clarke can you point me in the direction of the service bulletin. I am having the same problem with my aux fan fuse
 

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1994 E320 Sedan
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Discussion Starter · #17 ·
Clark, I'm in for one of those kits. Thanks for looking for them. I'll PM you off-thread.

How do those things install? Do they thread into the top of the fuse box where the fuse is, or do I pull the box back out and go in from behind? Just curiosity. Since one end of the fuse is on a spring loaded terminal, I don't have a clear sense of where the second of the two ring terminals would be.

Thanks!

--Karl
 

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Mr. Clarkz

I have a 94 e320 that the D fuse melted would there be a chance of speaking with you over the phone? I live in fort lauderdale and have some questions that you could probably help answering for me. I would also like to buy the harness for $45 that you speak of here in the forum. thanks!!
[email protected]

Leo R.
305-342-1600
 

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1993 400E
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Mr. Clarkz

I have a 94 e320 that the D fuse melted would there be a chance of speaking with you over the phone? I live in fort lauderdale and have some questions that you could probably help answering for me. I would also like to buy the harness for $45 that you speak of here in the forum. thanks!!
[email protected]

Leo R.
305-342-1600
I'll give you a shout tomorrow.

E-mail sent.


.
 

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1994 E320 Sedan
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Discussion Starter · #20 ·
Hi everybody, I'm back!

I got a request from another user for some pictures of the wires, and which ones go where in the fuse box. Before I do that, let me make something very clear:

I did this months ago, and can't swear that I have the order of these pictures exactly right. I think I've got it right, as they're in order on my phone. But I won't swear to it. So follow these pictures at your own discretion. Or peril. Or whatever.

Understood? Good! :grin Don't complain if your car burns to the ground because of any of these pictures.

These are in order, from the front of the fuse box to the back. So as you look at these pictures, the fuse box is oriented this way:

(Front of car)
Front of fuse box, where there are holders for four spare fuses
Rows
Rows
Rear of fuse box
(Rear of car)

These pictures are of an intact fuse box that I pulled out of a junkyard car. I used this to check my work when I had problems, and was very confident it had never been apart.

First picture:

Fuse box pics. by krshultz, on Flickr

Second picture. If you're paying close attention, you can see the same wires from the previous picture, in this one at the very top.

Fuse box pics. by krshultz, on Flickr

Third picture. Same deal, if you look at the very top of this one, you can see the wires from the one before it, to give you perspective of where you're at.

Fuse box pics. by krshultz, on Flickr

Fourth picture. Same deal.

Fuse box pics. by krshultz, on Flickr

Fifth picture.

Fuse box pics. by krshultz, on Flickr

Sixth picture. Not as much perspective available on this one but you can just barely see a gray/pink from the previous one.

Fuse box pics. by krshultz, on Flickr

Seventh picture. By now I'm less confident about the perspective and the order. At the time I did this, it was very helpful to me to mask off the other wires when taking pictures of individual rows. But for others' use later, the perspective of where this is versus where we've already been gets lost.

Fuse box pics. by krshultz, on Flickr

Eighth (and final) picture. I know this one is the last one because I can tell it's the end of the fuse box.

Fuse box pics. by krshultz, on Flickr

I hope that helps someone. More on this project later - it was not as simple as I'd hoped. In fact, this was the most hateful car project I've ever undertaken.
 
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