Engine wiring harness
 

Hey all, it's been a while since I've been on here but I do stop in from time to time to see what's going on and am always amazed at how helpful most are on here! Keepin' up the good work. :)

Trying to decide what we want to do with our nearly 18 yr old car that is still a good looker and simply very clean but needing some TLC at this time. It now has 113K mi and I'm suspecting that the harness is starting to rear its ugly head. It stumbles at start up from dead stop periodically and it will often times miss pretty bad when restarted after it has sat for an hour or two once it has been driven. (Needless to say, it has the original harness.)

Is it folly to think I can buy a used harness off ebay at half or more off the new price for a harness and expect it to serve us well for a couple years? Anybody reading this post ever replaced one of these things? I have read the Wiki on here regarding a DIY project and it is an encouraging piece as the author says he did his in something like 2-3 hrs but that most anybody with any mechanical ability could do the job in 4-5. I'm not necessarily intimidated by it, just don't know that I'm physically able to contort my body in ways I might need to do this! Like many of you, I try to keep my costs to a minimum by doing many things myself but I want to know for sure that what I'm about to undertake, I will be able to complete. Comments?

On a side note - I have a chronic transmission leak that has been in for service twice but no definitive diagnosis (until they are allowed to pull it and dig deeper). I'm fearful they will find that the front seal needs replaced and I'm not sure I want to shell out the big bucks to have it done.

The rear suspension is getting 'stiffer' and I suspect the gas-filled spheres are shot and need replacing. I'm sure there are many bushings needing replaced under the car, although it drives nicely as is.
Wifey is fine to put the $$$ into it and just keep it a couple more years but I can only look at the same dash panel so long until I get the itch! We have had this car since AUG 2007 so we're at 5 years and it's been a good car, but...:confused:

Bump...

Surely there's some thoughts here...somewhere!



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Here's my thoughts:

A new harness will set you back $700 from XXXX. Do it. Dont mess around with ebay alternatives or used this or that. Its not a hard job at all, no contorting required. Just take your time, follow path, unplug old, reconnect new. I did it on a 300E and it was pretty straight forward, easy.

Try taking the car to another shop and get a second opinion on your ATF leak. I had my 190E's transmission resealed after it started leaking from multiple points. It was $600 for the reseal.

Usually when the rear end gets bouncy is when you replace the spheres. Stiffer might mean you need to adjust the SLS level rod, it might be adding more fluid than is necessary.

Thanks JamesDean for your input!

May I ask how long did it take you to replace the harness? What car was it? Mine is the E320 wagon, is it easier or more difficult (in your opinion, of course)?

I will take ax look into the rear leveling issue. Thanks...

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I did it on a 93 300E. It had the same engine as your wagon.

I would say that on a scale of easy-to-difficult with easy being an oil change, to difficult being internal engine/transmission work... That it is a 3.

In terms of time, I would say no more than 2 or 3 hours. Just take your time disconnecting things. Lay the new harness on top of the old and go one connector at a time. You'll probably get it done in less than 2!

take pics, go slow, label some stuff if you have to.. i just rebuilt/installed my harness.
the rebuilding took a while though.. but yeah taking the harness out probably the part where the ecu was the hardest cause my clips were stiff

other than that it was fairly easy

Thanks guys for the supportive replies! It does give me more confidence to pursue it. Now, to find the best deal on a harness!

JamesDean - you mentioned .com but when I go there and search for one, it simply comes up empty! If you could be so kind to provide a link to it I would certainly appreciate it. :)

Its best if you just type in the Mercedes part number in the search box on the right side, then hit the drop down box and select OEM catalog.

It'll go to another window and you'll have to select Mercedes and then hit search.

It looks like there are two harness to pick from, you need to look at your car's vin number to see which one yours takes:

http://i.imgur.com/qjpqXl.jpg

Then take that 124xxxxxxx number and punch it .com

Is it worth putting 2k in the car...or is it better to spend that money on another?

I guess that's the question

The problem with that is, you might need to sink 2k into that other car for another reason.. If OP likes his car then I'd say do it.

Thats my view at least when it comes to my cars. I like them, so might as well fix them up. I've got $600 in a front end rebuild on the way for the 420...after that another 600 for the 190E's front end. Well the 420 is my parents so its their 600..

Thank you, I will do that!

I hear what you are saying. If I can do some of the repairs such as this wiring harness, then I am saving the labor costs. As far as my accumulators, not sure if they are actually bad until I do some testing of that system. I was making an assumption that I was going to need to replace them....but perhaps not. We'll see.

Thanks for your input as well :)

Ouch! I know, it's better than $1,100+ @ dealer...

I know the car needs it and I'm putting off the inevitable by delaying it. What concerns me is frying an expensive computer or the car simply letting us down sometime when we are least prepared! So...I will likely go for it and do it, I'll report back when completed ;). Heck, I'll go ahead and give it a new set of plugs while I'm spending $$$ and time.

PS: If anybody has a better lead on a better price, please, don't be shy :D

I just finished rebuilding my engine (M119) wire harness from scratch last weekend. I learned how to solder on youtube. I got the wire from amazon. I got a headache from trying to figure out which wire went to which connector. Thankfully, another member of this forum sent me his old harness to use as a model, and this also provided me with some of the plugs. All in all, it was a really large undertaking for me, and I am used to doing complicated work. It is amazing what a difference the new harness made. Now it is very powerful and very smooth, like a 400E should be. Total cost: $75.00

My hat is off to you my friend!!! THAT is indeed a huge undertaking for any DIY'er - no matter what anybody says :eek:. Good job!

Yeah, I'm sure the car will perform better and will be more reponsive and no infrequent misfiring and such.

I will likely need to do a throttle actuator rebuild/replacement at some point as well. But, one thing at a time..

My ETA is next. I should say that I got all of the DIY instructions right here on this forum. The pictures were great. A few years ago, I searched this forum and was able to swap out my dashboard in my 88 300E. Now that was alot of work! This site is invaluable.

If that the shipped price, you might be able to talk to them and get shipping lowered a bit. Thats what I've heard people doing.

You probably wont find it much cheaper unless you DIY it. All the newer harnesses are made by Delphi I believe.

@JamesDean...that was with Free Shipping however, I wanted to order 6 new Bosch plugs and they were gonna charge $7.95 shipping because they were coming from another "warehouse"! So...

I dig deeper into the web and find it at with free shipping. So I ordered it from them and the plugs from the .com and saved about $40. Hey, every penny adds up!



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@cmcdonnell - indeed, this is one great forum, without a doubt! Truely a great resource...thanks guys :-)


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Well, the fresh (build date 11/18/2011!) new harness arrived today so I am going to have to get myself psyched-up to start this endeavor! But it should go alright as I take my time and methodically go about disconnecting old plug / reconnecting new plug, starting up behind the battery and following the Wiki here on the forum.

May not get the chance tho this week as we have a full one in store, but hey, the 6 fresh new BOSCH spark plugs are not due to hit my doorstep until Thursday sometime! :)

Wish me luck and....uhh...PLEASE be there when I might need a helping hand!! As always, I know you will. Thanks...;)

Dale

Attachment 104690

Attachment 104691

Get on it! I'm usually on here during the day so I can reply depending on work load.

Just remember to take your time. Lay them side by side and work one plug at a time. I would recommend first removing plastic cowling that might be in your way before starting. I would also say start at the end with the big plug!

Thanks man! I've read a lot on this subject and indeed, you are right on it as regarding where to start and all your other suggestions! I appreciate your willingness to be 'on-call' sorta :D

Stay tuned, I'm likely not gonna be on it for several days maybe not til next week but I'll let you know when I intend to start it...;)

Hi Dale,

I replaced mine about two years ago...95 e320 wagon. It took less than 2 hours taking my time. Remember to disconnect the battery and go slow! Plug by plug ....one at a time. As I recall I had a slight dilemma with which harness to get but Phil got me all straightened out. I think the 95 had two harnesses depending on the VIN. I remember one plug was a little difficult as it was towards the bottom middle of the engine, I actually got under the car to get at it. But it was a straight forward process. Good luck.

When I replaced it...it didn't help my intermittent start issues (ended out being two fuel pumps), but I'm glad I did it anyways. The old one was actually in kinda good shape.

darn havn't been on the forum enough

but
Mercedes repair and restoration

this guy fixes wires/eta's and hes good.. but the quote was quite expensive to patch my harness up.. cost me 40$

don't forget the wiring harness either.. which is MUCH cheaper though

and go slow!

Hey thanks, but no thanks! Something as intricate as this piece of hardware on this or any other car, I simply wouldn't waste my time and $$ on, what I consider, a risky repair.

He may be "good" but I'll (already have!) spend the extra for a newly manufactured harness and install it myself - saving on the labor part.

If this worked for you, I am happy for you and glad you were able to cheat "Murphy"! I'm just not that fortunate most of the time...:D

Thanks for the encouragement! I had a really busy weekend and wasn't able to tackle it but hope to get on it by this weekend. Every moment driving it with the bad one just increases the chances something will get shorted and then BIG $$$$'s will start flying! Thanks again and I'll post my progress as it happens. :)

1-2 hours max buddy :)

took like a week to do it myself though.. make sure you go slow, use wiring diagrams, take pics if you have to! and or label your wires with some paper tape or painters tape thats what i did

Now wait a minute here...! You first tell me "1-2 hours max..." then you go on to say that it took you "...like a week to do it..." :eek: !!!

I take it that other "life" related things interfered?! Hope you are correct that it only take a couple hours cuz I'll be a happy camper if that is the case! :D

EDIT: Where might I find an appropriate wiring diagram? Anyone have a link to one on the internet? Thanks

OK! Let's get this show on the road!!

Things are moving along pretty well, ie, battery is out, plastic cover hiding the computer interface plug in is off, cross over pipe is off, some of the weatherstripping is off or pulled back as needed, etc.

Stumped at the moment as to how to get the large plug end thru the bulkhead without tearing up the 'insulation' type foam that serves as soem insulation against the metal. Anyone have a suggestion on this?

Thanks...

Does the plug fit out opening? You should grab a camera and post pictures when you get stuck on things. That would help us out.

No it does not. Seems I need to remove the foam in order for it to slip thru the larger opening behind the foam (in the bulkhead).

Sorry about lack of pics but I will try to put some up here in a few...thanks!

Here are a couple pics of that area where I need to thread the plug thru...

Attachment 104940 Attachment 104941

Remove that black plastic piece above that area and you should be able to get the wires though. I think...

I think you are correct.. I've been side tracked changing out the spark plugs!

Getting ready to get back to harness...:D

Well, I'm anxious to fire it up but I have an issue with a broken (brittle) vac line as seen in pics at front of engine underneath the cam end cover.

What is the vac line running to? Not familiar with the 'block' it connects to at front of motor...:confused::confused:

oops! I forgot to include pics in the previous post but it's a rather moot point at this stage of the game as I have been to the dealer and picked up a meter of small vac line and installed it.

The car is back together and is running very nice! The spark plugs I pulled out of it were pretty well shot and gapped at ~ .050! It just purrs and is very responsive at the throttle as it had gotten to where it would oft times hesitate slightly, sometimes completely stumble and backfire.

I'm kinda surprised at the relative good condition the old harness is in - I mean, it's NOT visibly crumbling or crackly sounding as I handle it. Perhaps it's a different story if one would cut away the outer 'tape binding'.

Thanks for your help and advice and now I am going to enjoy a nice ice-cold beer! Cheers :beer:

EDIT: BTW - If anybody is interested in the old harness for the ends, please PM me and we'll discuss details. Better do it quick as I tend to not allow stuff to lay around....just sayin'!

How long did the job take you? Easy? Hard?

Started the project at 9 and had it cleaned up at 3...

BUT...there was a trip to the dealer and time to get the old spark plugs out and the new ones in and a few minutes to stretch my back and legs (not as young as I once was, ya know)!

Scale of 1 - 10 I consider it a 2.5 - 3 (1 = easy / 10 = difficult). It really is a pull and plug deal most of the way except there's a couple places I needed to go ahead and unplug several of the original connectors so I could get the old one out of the way. :D

Does the place where you got the wiring harness make them for various other w*** model Mercedes. I wasn't certain from the reads if they had to be special made maybe?

You can get them for pretty much any Mercedes. The one 85 DSEL bought was made by Delphi (one of the largest auto parts suppliers).

The harness DSEL bought is usually carried by a lot of places because its a known problem on a variety of Mercedes of that era.

If you're looking for something less common or known like that your best chance it so order it from Parts.com using the part number for the harness.

Sorry Rebe but I was out for a while this evening and didn't get to your question until after it had already been answered. JamesDean pretty much said it all! Just search the web for the product by the part number and you'll get many hits to choose from. As JamesDean said, try Parts.com and I would suggest the place I got mine I think it was XXXX. I think I mentioned the place in one of the earlier posts in this thread. :)