Engine harness replacement for '92/'93 500SL
 

Hi all

Long time no see I know but the time has finally come to change the harness (due to intermittent ASR light and visual inspection of my harness) and I've been looking through many pages here including the DIY section, but just can't locate a few things. If someone could point me in the right direction it would be very much appreciated:

1. Where can I purchase the wiring loom from (preferably in UK, but no harm in shipping from Phil if he carry's stock)

2. I see there are upper and lower parts - rough cost for individual and both?

3. I guess I should do both?

4. Does the Electronic Throttle Actuator (ETA) unit connect to the new harness? If so, I seem recall from memory I need to strip the ETA out also and rewire this manually. Does anyone specialise in this repair - I seem to recall a few US places but anyone know of any UK based?

Many thanks
Lea

I'm speaking from 1996 SL600 experience, so there may be differences.

You should be able to purchase at any MB dealer. No one will have this in stock.

As far as I know the only lower parts are the oil pressure and level and alternator, starter harness. I wouldent see a need for both except the lower one is probably under $200 US the upper is probably over $2000 US.

I don't have ASR, I have ESP which has its own separate harness.

I'm not sure what you mean by ETC (Electronic Transmission Controller?) The wire harness connects directly to the ECU (Engine Control Units) Thats the LH units for pre96 and the ME units for 96 up. I was unaware that your car, pre 96 SL 500 had an electronic shift transmission. If it does it is not connected to the engine harness.

In my case the connectors for the ECUs just unplug from the top of the two ME units and are easy to remove. I think your connectors are on the bottom of the box, but my guess is they come out as a separate connector.

For the 1996 SL600 this appears to be a very simple job. Remove 3 connectors from the computer box and disconnect everything from the engine. which all seems to be very exposed, accept I cant say the knock sensors are easy to get at. They might require removal of the intake manifold.

Hi John

Thanks for all your comments, yes sorry the ETC was a typo - I've corrected that. I have the infamous ASR light syndrome which is indicative of either potentiometer wear in the ETA unit itself, or/and ETA wire insulation breakdown. In fact today I inspected a few wires connecting to the variable camshaft solenoids and indeed they show the classic insulation cracking!

As I need to remove the manifold to get to the ETA (should I replace the gasket also?), I thought I'd change the loom, but at $2000 that's not pleasant!

Oh and forgot to mention that my 500 is an LH with semi electronic gears.

I wonder if there is a step by step guide re loom replacement? Also I'm sure there's a huge thread on here regards to rewiring the ETA, but I'm hoping there are a few UK companies who now offer this as a service - a new ETA is 1000UKP!!!

No need to do the lower until you see a problem there, unless you just want to. In the U.S. the upper harness should be around $600 for that car, not a difficult DIY job.

Well the last person who posted says $600. Thats a good deal if its true. I'm only going by the $1700 price I got for my 1986 560SL not nearly as complex, but they dident have such a huge replacement campaign for those.

There is a step by step for other cars in the DIY links.

On my 96 SL600 the transmission is electronic and the trans wire harness is separate and does not connect to the main wire harness.

I should be in wire harness hell all day today. Or should I just stay inside in the cool air conditioned house.

$600 - now that's more like it. Has anyone got a link to a supplier - pref one that ships to the UK?

I new Jim (http://pages.prodigy.net/jforgione/MB_S500.html) had some excellent pages covering ETAs and it seems my low oil pressure issue - now I found his site again - thanks Jim!

Also, it seems like I don't need to remove the manifold to get the ETA out - that's handy ;-)

My father-in-law happens to be a mechanic (has been for over 50 years) so if it's s DIY job then it going to be OK I think.

He recommends that I locate all the parts first then we can review and fit :)

Part number is 129 540 77 05, list is $745, which is the very high end of the 119 wiring harnesses, most are more like $600-650 list. It's a dealer part, just need to call the usual suspects, Duval, Caliber, Park Place, ask for the best price, expensive parts are often negotiable. Phil doesn't list it but may be able to get it. $669 here - http://www.trademotion.com/partlocator/index.cfm?siteid=214269 , enter part number, i.e. 10 percent off, but other than that no links, just need to make the phone calls. Not sure about the international shipping.

Thanks for the part number deanyel. Do you think there will be a difference between US and UK part numbers?

I'll try my local dealer first (for a laugh), then hit the US ones I think. I'll ask Phil also, but he seems to have a ban on international shipping which seems rather odd?!

Lea

I would think part numbers are the same but you just have to get yours. No part number changes according to EPC so you could try to get it off the car too, near the source plug. You may run into more bans on international shipping, not sure, MB sure doesn't like dealers selling cars across borders.

especially when 2USDs = 1GBP ;)

Great, it's actually on the loom eh, that will definitely make things a little easier.

You mention the source plug, I took a look around in the engine bay today but couldn't find it but I'm assuming it's a the rear of the ECU aluminium case?

Lea

Should be somewhere in the right rear of the engine compartment - should be able to trace it backwards from the wires to the injectors.

Just order the loom from the dealer, I just bought one for £481 less 10% pt no.1295401706 Its dead easy to fit about 1.5hrs Regards Linds

The loom connects to the side of the ECU alloy box, The box or ECU do not have to be removed as there is a link harness from the side of the ECU box to the bottom of the ECU

I did mine last year. Both the harness and a new Throttle Actuator. The Job is pretty straight forward. Just lay out the new harness on the engine before you remove the old one to get a better idea of the routing. Be extremely careful with the throttle body remove and replace though. I managed to bump the hot wire sensor and it cost me another $900 to have the diagnosis and repair.....

Phil did me right on the harness and ETA.

Try www.speed-autoteile.com in Berlin for your harness, they have good prices.

Most US dealers wouldnt ship to you directly, you would need a middle man.

I am going to order a harness for my 500E. It is really falling apart. =(

Hi Guys

Thanks for all your comments.

But they are only 300GBP in the US! All I need is the middle man.

I have a MB parts/dealer just 15 minutes away so if any one from the US needs UK/Euro parts that you can't purchase then I'd be more than willing to do purchase on your behalf and ship - assuming you would purchase and ship a wiring loom for me.

Please do let me know.

Re the ETA, what did you do? Rewire yourself, purchase brand new (cost in USD?) or send away for refurbish?

(http://www.beckmanntechnologies.com/products.html) or similar??

I wonder which ETA I have? Anyone got an EPC handy?

Cheers
Lea

Many of my customers write about where they have purchased MB 'stuff' at reasonable prices.

One said he purchased a wiring harness that listed for $571 for $521 at this site: http://www.europartsdepot.com/default.aspx

As far as ETA repair, I recommend Beckmann Industries. As you've read (in Menu#24), there's some horror stories.

Stay well. . . :)

Anyone who would help you would need a part number from you. You will be stuck with whatever you specify because these are non-returnable items to say nothing of the difficulty of a return. The Euro EPC shows both 1295407705 and 1295401706 (U.S. EPC shows only 7705) and is curiously silent on supersession and VIN split. Perhaps they both work but you would need to decide which you want, or if either would suffice. PS - it's possible that only 7705 is available in the U.S.

Hi Jim

Your pages are always a saviour, and you got it, I've read both your ASR and Oil tube articles thoroughly - and so many thanks for providing such great info.

I'm going to grab a cost and correct part number from my local MB parts dealer first, then maybe even confirm with the actual one on my car first I think.

Cheers
Lea

Today I wondered to my local Merc dealer and got the part numbers/cost for my VIN:

Engine Harness: 1295401706
ETC: 0001415225

Anyone want to guess the cost here in the UK?

Suffice to say I need to refurb the ETA - off to Beckman for a quote and attempt to purchase the harness from either US (if they carry stock) or Europe!

BTW - anyone tried http://www.bba-reman.com/catalogue/DetailedProduct.aspx?DetailedProduct=1098 ??

Lea

Uhm, I see the 7706 doesn't seem available in the US - but is it actually different to the 7705!?

The problem is we use right handed vehicles which could mean many subtle differences :(
The quest continues...

I see Beckmann have my ETC for 923USD - is that refurb or brand new? As I'm and Electronics Eng. soldering posses no issue so maybe go for the wire replacement first?

One last point, if Beckmann simply refurb (and request my 'core' in exchange) how do they replace the pot when there's no known source? If they have a source, surely so do we?

Uhm, still many unanswered questions.
Lea

I think you may have meant 1706 rather than 7706. As pointed out earlier the Euro EPC shows 7705 and 1706 - with no mention of vin split or supersession, which is strange, never seen it before on the U.S. EPC, but indeed it could be left version right hand drive. The part number off your car would be a very good clue. It would also be helpful to try to get the parts person to explain the existence of the two part numbers on the Euro EPC.

"Trade secret" - apparently the ability to re-deposit "resistive" material. This according to JimF's site, ASR page #24 - http://pages.prodigy.net/jforgione/MB_asr.html - update comments of 7/14/05 and 1/23/05. But true someone has to be making them or it wouldn't be possible to manufacture new ETAs. But distribution can be tightly controlled when they want it to be. It would appear that Beckman has not found a source. And these pots were never the replaceable, standalone type to begin with.

The wires can be done if you're 'dedicated' . . and for that amount of $$$, who would'nt be?? LOL . . .

As the info states, Beckmann can 'sputter' to refurb them but, many times, the Ref Pot is ok. One of the large failure item is the 'clutch'; that's what was bad on my ETA. That part was replaced/rebuilt.

If you have nothing more than bad wires, then it certainly fixable yourself but it's got to be a ***** of a job. Check Pete's site for this pictorial. . .
http://v12uberalles.com/throttle_actuator_rewire.htm

I would be willing to be the middle man. But the best price I got was $820.00 US. That would be plus shipping internal US ~ $25 than + shipping to UK ~ ???? then plus taxes and customs at your end. It doesn't seem like a great deal to me considering the excess logistics and as one persons said is it the right one.

I believe that's a refurbish price . . .

Not necessarily! If there's a source external to them, there's no reason that we have any "rights" to them.

But I believe Beckmann can refurbish them in a 'u-electronic' facility. Easy to re-sputter resistive material in the proper facility.

Fortunately, the Ref Pots seem to be a lot more rugged than first thought. The 'wires' seem to be the Achilles heel with the magnetic clutch a close second.

Whoops, yes indeed - 1706.

Thanks John for your kind offer, if I can locate a 1706 available in the US (and <<<800USD) I might take you up on it.

Re the pot, it wouldn't surprise me if refurb companies simply swap pots around somewhat, i.e. if only 10% of units have pot issues and the rest cable/clutch then you'll soon build up a selection of working pots assuming you request the 'core' as part of the deal! Then no need to 'sputter'.

However my unit has only 89,000 miles and I would hate to see it replaced with an unknown.

They previously had the EPC in customer view, but now it's gone 'round the back' which is bloomin annoying as I used to have a good chat alongside lots of finger pointing...oh well!

Any reports on of bba Jim?

Thanks all
Lea

I don't blame you . . that's why I had mine rebuilt but I did purchase a 'new' unit which is presently in my car. One of these days, I probably will sell it.

I have no feedback on BBA other than what's posted for that page . . .

Sorry, I misunderstand. Do you mean that's why you purchased a new unit i.e. a rebuilt unit may have a significantly more worn pot than your original?

Thanks

At the time of the ETA failure, I got a great deal on a new ETA from my tech's parts supplier.

Later, 3 years or so, I decided to have it repaired to see what failed w/ the ETA, plus I'd have a spare.

Menu#24 details the time line; original ETA problem in 2003 and then the 'flairup' in 2007. I thought that the original ETA was going bad so I planned on swapping it with my refurbished original ETA. As you see, the date is "Oct 2007" when the Neutral Safety Switch was finally diagnosed as the culprit.

BTW, the ETA was refurbed by Beckmann and it's still in-the-box!

A couple of links I have been pointed at:

http://www.pelicanparts.com/euro/catalog/shopcart/Z108/POR_Z108_FULint_pg2.htm#item8

http://www.benzworld.org/forums/w140-s-class/1363884-make-your-own-wiring-loom-heres.html

Maybe I should remove the parts and investigate before purchase. Bet the pot's fine in the ETA - and it can be easily checked with a constant voltage source ;-)


But still can't locate the 1706 :(

Lea

Did you ever confirm that your original is a 1706?

Well I haven't pulled the loom out yet but MB confirmed when they checked using my VIN and EPC - however it's not always correct. Had a previous saga with my electric aerial where EPC promoted Hirsh but I have the other one (can't remember name now).

Is the 1706 identification easy to reveal?

Just lifted the ECU plastic cover and there it it - printed on the loom just below the connection to the ECU is the full 1706 part number.

That may point to it being a right hand drive specific part, since Euro EPC shows both 7705 and 1706, and U.S. EPC shows only 7705. In any case 1706 doesn't seem to be available in the U.S. Of course you can still ask your parts guy why, as you've heard, the EPC shows both numbers.

Unfortunately the parts guy will just say, "no idea mate, you just need a 1706" :(

So, what I need to do is compare a 1706 and a 7705, anyone have a spare/old 7705?

Thanks