W126 Main Wiring Harness R&R
 

I have concluded that the poor charging problems in my '87 560 SEL are due to damage to the wiring harness right at the altenator connection (lots of corrosion and probably over half of the wire strands broken). It appears that this harness is rather complex and goes just about everywhere under the hood, starting at the battery:confused: .

Couple of questions:
1. Are there any ticks to installing the new harness once it arrives (P/N 126 540 2530)?
2. Are there any other issues that might be contributing to my poor charging problems (battery and alternator are brand new and in good working order)?
3. Would it be possible to repair/replace just the damaged portion of the harness or is this just asking for more problems in the future?

Thanks
jlc

Anyone with any suggestions?

The new harness arrived last night so I'm going to be installing it soon.

Thanks
jlc

Jeff, not tips but what did they charge for the harness, and update us to let us know how it goes.
m

i'm curious too
 

Have much of my engine torn down, and the harness connections look pretty straight forward on the engine. Mant of my connectore are brittle or broken. No two connectors are alike, so almost impossible to err in that regard i would think. If the connection at the fuse panel is as clear as on the engine, should be a smooth job.
Where did you source your harness? And would you mind sharing your cost for it?

An Update
 

Still waiting for the right combination of time, good weather, and daylight to install the harness. I'm tempted to do it sometime over the next week or two while we are visiting family but don't want to get into a situation where the car won't run:eek:

Price wise, it seems that everyone's about the same since this is a Mercedes only part. The dealer wanted $179 + tax but couldn't find one in the US so it would take over a week to come in from Germany. I ordered from *************** (actually on the phone) and got it for $190 including shipping which worked out to be about $0.25 more than the total would have been at the dealer but they had one in their warehouse and got it to me in two days.

The connections are definately all different so crossing wires is impossible. My only concern is access to all of the connections, particularly the two under the engine near the starter. I have no idea what they are for and can only guess at location right now from looking at the harness.

I'll update more when I finally get around to the install (probably on the 26th if not before).

jlc

Thanks
 

That's good info on the price. i would have guessed higher, but at that money i'll do mine once i get the head back on and make sure she's running. Is it a "plug & play" kind of connrction at the beginning too? Would love to see a picture.

don't forget the voltage reg on/in the back of the altenator. it's the brush assy which may have been all that was wrong with your charging. they sell for under 20$ if your's has 100k on it just change it out you'll be thankful later when your alt doesn't quit on you.

tks
craig

Craig,

Thanks for the suggestion however the altinator, complete with voltage regulator, is new and has tested out just fine.

jlc

Final Update
 

I got the right combination of time, good weather, and day light on the 26th as I had expected. I also got some assistance from my dad which was great - he did the goferring so I didn't have to keep crawling out from under the car.

All together, the installation took about 45 minutes from putting the car on ramps to driving it back off. Typical of my experience with this car, everything snapped into place like LEGO blocks. The hardest part was getting the screw that holds to small lead to the starter solenoid to thread into place. Everything else was very straight forward.

While I havent' had the chance to put a meter on the system yet (my dad's turned out to be dead), the faint glow on my dash warning light had gone away.

Thanks for the input and suggestions from all.

jlc