Greenie wiring harness E320 interchange question
 

Benz friends,

There are two wiring harnesses specified for our 95 E320 wagon.

MB part # 124 440 29 33, which we should have on our car, and another, MB part # 124 440 56 32, which is specified for an earlier chassis than ours.

I just salvaged a near new 124 440 56 32 from a 93 300E with a M104 engine.

The 93 also specs a chassis break point and the exact same part numbers are specified for the 93 before and after the break point.

Whilst I'm not surprised to see a mid year break point, am VERY surprised to see the same parts numbers and two break points in two different years.......


All Parts Express also says this:

(124 44056 32)
Early Version w/ Round Thermostat Sensor Plug;Engine Wire Harness w/ Round Thermostat Housing Plug;

(124 440 29 33)
Late Version w/ Square Thermostat Sensor Plug;Engine Wire Harness w/ Square Thermostat Housing Plug;E;



Does anyone know if I can substitute the 56 32 harness for the 29 33?

This literally is a thousand dollar question......

Many thanks,

Jim Freeh

My model takes the 124-440-29-33. I had the 124-440-56-32 shipped to me by mistake, so I had the opportunity to compare the two. They are not interchangable unless you're willing to cut and solder one or two connections. I'm not completely sure that it would be a one-for-one substitution of connections. This was eight years ago, so I'm working from memory, but I did keep notes on those numbers.

The 124-440-29-33 wiring harness was more expensive. I too was told it's the later model version.

I'm laying it out on the engine now and comparing.

Another note: Our car has the air pump and it looks like the earlier version does not have a pigtail for the pump. I didn't notice any air pump while removing the harness this morning, so maybe the 93 doesn't have one....

Only place ours is deteriorating is under the plug/coil cover, so I may just try to splice that section into our existing harness.....

Also noticed some Pick n Pull hacker has clipped the lead to the T-stat housing..... otherwise the yard harness looks very nice.

Jim

my 93 has an air pump...ask me if you have questions about the 1993 layout..it is exactly the same engine as the 1994...maybe some accessories changed?

I believe the break in harnesses is the ignition type. Earlier cars had a distributor, later cars have a coil-on-plug ignition. I can't think of a way to adapt an older harness to a newer car, and going the other way might be just as difficult.

Both harnesses are for the coil on plug style ignition.

I'd say at least 90 percent of the harness looks the same.

Jim

Jim, if you replace all of the sensors including the crank sensor, either harness will work!

In looking over the original harness, I'm only getting significant insulation crunchiness at the rearmost coil pack.

I've disassembled the 93 harness, and I'm going to overlay the portion of the harness that goes to the 3 coil packs.

I've got the ground wire (pink) singled out to it's grounding lug on the left inner fender, and I'm going to solder in the 3 black coil leads just downstream of the large connector that attaches to the brain behind the battery.

Once in place, I'll cut the original section at the point it enters the cam cover and enclose the new wires in a length of split plastic loom cover that is common on US cars.

I'll finish up after work today, should have it together this evening.

Jim

you will find that every single wire of your old harness is corroded/ will corrode in the near future...i would recommend against wasting a perfectly good harness and soldering it into a crumbling one....

just change-over whatever plugs are different and use the new one.....

I considered that before I got into it. I laid the new one over the old one last night and checked for anomaly. Some runs have different lengths of wire and would require extensions, and then there are minor differences like the t-stat wires having four wires on mine, and 3 wires on the new one.

I can pay $1069 for a new harness now, or I can splice this one that I paid $20 for into my existing one.

An examination of my current harness reveals that I've got some time left before other wires deteriorate. I'll also keep my eye out for another lightly used harness, one that is the correct part number, while running with this fix. I'm betting I can grab the right one before this one gives me any more trouble. The car is not giving me any trouble right now, runs just fine, but the last time I changed plugs, I noticed the insulation on the wire going to the rear coil getting brittle, and that's the only place I've observed any deterioration.

It's painful to spend that kind of money on a car that isn't worth all that much, even though it still looks close to new..... That's got to be close to 20 percent of the car's value.

But, thanks for your response, I had thought about selling this one and applying the cash toward a new one, but once I discovered the t-stat lead had been cut, I was more reluctant to offer a damaged one up.

Jim

I agree with the rational completely. but when i re-did my lower harness, i tried to do the same thing : resolder a wire to it... even just moving it slightly caused the insulation to crumble beyond belief......so be very careful or you end up with neither harness working after this...unless you dug-into one of these crumbling harnesses, it is hard to imagine how bad they are...mine was seriously scary:eek:

good luck man, post some pics if you can

If you're trying to pay the most you could pay more than that. If you're trying to pay the least Parts.com is $741. Or rebuild the old harness entirely. This splicing idea doesn't sound viable.

Splicing should work just fine. I've heard of people just replacing the bad parts of their harness with new wire and no issues. Just need a lot of patience and some good notes/pictures/memory.

Hey Jim,

Where do you find the P/N on the harness?

Thanks!
Pete

White tag near the plug for the controller behind the battery.

Original harness had no tag....

Jim