My 1992 W140 wiring harness insulation has gone brittle. I would like to replace the wire. The engine compartment is pretty hot. What sort of wire should i used? I believe i need wire which is resistance to heat, chemical, oil, etc. Please advise what type of wire should i used.
Thanks in advance guys. Appreciate your help.

Here's a good site:

http://v12uberalles.com/index.html

and here's a good article:

http://v12uberalles.com/AMM_rewire.htm

and another one:

http://v12uberalles.com/throttle_actuator_rewire.htm

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

119 motor or 104 motor? A 92 104 motor isn't known for having problems. Marine wire is probably the toughest that you will find - at any good marine store.

Mercedes makes a replacement harness for your car. If you plan on jury rigging it you might as well sell it and get a Honda to modify to your hearts content.

Absolutely!

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

IMHO, a capable person can make up a usable and durable harness. I don't know if I would call that jury rigging, though a purist might.

Anyone can stroke a check for a new harness, but someone who is capable of making a new harness and drives a W140 is looking for a challenge and trying to upgrade the car. I doubt if they are doing it to save money, because their time is worth more than the cost of having a grease monkey install a new one of dubious quality.

I repalced the wiring harness on my 1995 SL500 (Similar Engine) after the dealer quoted me $1600 for the new harness. (No Labor) He assured me that it was made to the same specs as the origninal harness. There are many comments the subject on this and other forums, so I won't comment further and let you decide on the quality and merits of this particular Mercedes part.
I found the job quite easy. I used Belden 656702,18 AWG Style 1569 - Rated at 105 deg. C. This is a common oil and gas resistant CSA approved wire. (Slightly larger than orginal). Marine wire is a good alternative but get the UL or CSA specs on-line first. I reused all injectors and connectors by carefully soldering/heat shrinking to the new wire.
The key to the job is to get a schematic ( ALLDATA DIY ) and a good ohm-meter and spend an evening planning - marking and preparing. I did this on a Thursday night(3 Hrs) and did the job Friday night (5 Hrs). I cleared all the codes and went for a ride. I did this in early June. There are high temperature wraps available from places like McMaster Carr which I purchased but did not use. I went the summer watching the harness and measuring the wire temp. after long drives in 90 deg F plus heat. The wire never got above 70 deg. C. I will add the temp wrap next spring.
Easy job - under $30 - Engine runs great. E-Mail for Pics and more details.

FYI, Honda makes replacement parts too. This wouldn't solve the problem - he'd just start modifying the Honda. I'm skeptical of this theory that repair methodology - first class versus compromise - should be based on the original price of the car. A car that has no market value has no market value and should be treated accordingly. What it cost originally isn't really relevant. Of course some of us just think building a wiring harness would be great fun - Mercedes or Honda.

Your not "upgrading" the car. Your making an inferior wiring harness that will look bad and may cause unexpected problems with the car. If you can't afford to fix your car correctly and balk at the price of parts why not look at a cheaper car? Would you stick a VW bug engine into it if you threw a rod? Maybee a GM 2 speed transmission if you needed a transmission rebuild?

Im far from a purist but if I opened the hood and saw some cobbled together wiring harness under the hood the first thing I would do is shut the hood and leave. Your absolutely killing the resale value of your car that way. Many of the people who specifically look for 140's know 140's so your market would be first time MB buyers that did not know what to look for.

The new wiring harness is a different kind of wiring that does not break down over time. If you want a real scare just wait 5-7 years when the wiring harness on the inside of your car starts to break down

Its fortunate that you never owned a classic SL or vintage Rolls Royce or Ferrari. ALL cars go through a period of depressed value. You know those $100,000+ SL's you see at the car shows? They hovered around the 5K mark for a while before their real value was discovered. Those Multi Million dollar Ferrari's did the same. While its unlikely the 140 will ever see any real collectable value you never know what the market will do. The value may eventually rise as the market learns to appreciate its build quality because of the absolute crap thats being produced these days.

Butchering a car because your too cheap to pay for replacement parts is a really sad thing to do. If you want to tinker go build yourself a heathkit tv or something as you might learn something in the process. Putting cheap replacement parts on a car is not the greatest thing in the world but its leagues better than what your planning. By the way guys have you done all the calculations on the resistance changes your harness will cause? Do you have a schematic of the car so that you can use the correct guage of wire and wiring that will take the amperage? Found a solution to provide the same RF shielding that the original harness provided? Price some of the computer modules for your car before diving into your project and decide if you want to spend the money in the event that you connect a wire in the wrong place. Theres a lot more to the process than connecting a bunch of wires with wire nuts in your garage.

[QUOTE=rchase;1277856]Your not "upgrading" the car. Your making an inferior wiring harness that will look bad and may cause unexpected problems with the car. If you can't afford to fix your car correctly and balk at the price of parts why not look at a cheaper car? Would you stick a VW bug engine into it if you threw a rod? Maybee a GM 2 speed transmission if you needed a transmission rebuild?

QUOTE]


Who mentioned anything about being able to afford to fix the car? My Jaguar uses a Delco(GM) nitrogen sphere for the ABS brakes, I bought a new one at the Cadillac dealer for 1/4 the price of the holy Jaguar re-boxed part. I guess by your logic, I have defiled my car by using a GM part because I balked at Jaguar's list price.

The Powerglide comment is pretty funny, because the top flight Mercedes 300d Adenaur model used a Borg-Warner slushbox. Likewise the VW bug comment, many Porsche products used VW parts, even complete motors, a la mid '70s 912E. I won't even mention the Posrche 914, because it was only sold as a Porsche in the U.S., everywhere else it was the replacement for the VW Karmann-Ghia.

You don't know how close to the truth you are.

People really don't realize how different car marques share the same parts, with widely differing prices. For example, Mercedes 190SL models and late Porsche 356 models share the same front turn signal lens assemblies. The 356 part is much less than the Mercedes one. Rolls Royce used a GM TH400 transmission in the Silver Shadow model, along with GM power steering pumps and steering boxes. Even the power window motors in my XJ-S are GM parts, down to the GM part number. The issue with the OEM harness reminds me of British planned obselescance and Lucas electrical products.

I think more people are scared of $5000 a/c repairs with the W140, rather than who made up the harness.

I know a guy with a Ferrari Dino and a Daytona, both have elephant hide covering the dash. The Dino has MSD ignition boxes hidden in the oem Ferrari ignition units. The Daytona is going to get a hidden MSD ignition as well. He bought both of them new in Italy and knows full well what they are worth today.

How do you know that someone owns or doesn't own a classic SL or vintage Rolls Royce or Ferrari? I know people that own one of each, and they look like they should be driving a 1986 Honda Prelude. One of them actually does drive a mid '80s Prelude.

[QUOTE=John Holmes III;1278014]My 126 has a GM A/C compressor. Im well aware of the different makes sharing parts. There are a lot of Rolls Royces out there with GM transmissions as well and Delco radios. I have seen many Porsche 912's with VW engines in them. These parts are interchangable and really are not on the same level as "some guy" with a big spool of wire and too much time on his hands and not enough experience to do the job right.

My point is there are two kind of car owners. Those who keep their cars running well and those that kill them over time with poor choices of modifications and being cheap with repairs. If you look at the Japanese car market for a moment (you mentioned Preludes in your other post) it is very difficult to find a car with collectable potential lets say a 300Z just for argument without heavy owner modifications. Many of the cars that have been modified the owners went into the project with the very best of intentions and overestimated their technical ability and have butchered the cars in the process.

Mercedes sells a revised wiriring harness that does not have the problems that the original did. That would only leave two reasons for not using the original parts. One of course I mentioned which is an owner who is driving a car they can't really afford to maintain. The second is the Japanese car concept of "modding your ride". Both tend to prematurely destroy beautiful cars and hence the reason for my posting. There are some cars that the parts are simply not offered for. Repairing or making your own wiring harness not only would be your only choice but would be a perfectly acceptable repair. These cars however are MUCH simpler than a W140.

I don't have a problem with people who are smart about the parts they put into a car. An A/C compressor is an A/C compressor regardless if it has a GM or MB part number on it as long as it was designed to fit the car.

But then again why should I even care. If you guys want to wreck your cars it just means that there will be more used parts on the market for other 140 owners to take advantage of. And you also might have a different philosophy of ownership than I do. Many owners have a disposable mindset with their cars while I keep mine for many many years.

I really wish you the best of luck if you decide to do it. I hope your harness fits the car well and that you don't blow any computer modules with short circuits and missed connections.

Problem is, it WON'T be an upgrade.

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

yes it will because it won't be made of biodegradable wire.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
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