AMGV12

Hey guys, I'm new to the site and need some help. I have a 1992 S600 with the problem that most of you have had or will have. The engine wiring harness is about done at this point and needs to be replaced. I brought the car used and the former owner took the car to a dealer in Pa that called them selves fixing the wiring problem by splicing into the existing system, and did the worst job I have ever seen. I plan on replacing the whole harness and need some DYI info or pictures if some one can provide. Thanks.

Jonathan Wallin

Hi!

I did just this last week and it took about 30 min.

It's hard to explani how to do it and I didnt took any pics. of it cause it was so easy. Just look how the old one is installed.
Remove the midle plastic cover on top of the engine to get to the old harness.
The contacts cant go wrong. You'll see exacly where each contact should go.

The Harness:

1. The harness concists of 12 small plug-in-contacts to the injectors. One for each cylinder. Unplug old, plug in new. Be careful not to break the small, plastic injection-contacts on the engine.

2. I think it was 4 or 5 other plug-in-contacts that should go to the waterpump. Very easy to detect the connection points! It cant go wrong.

3. In the other end of the harness there is a big plug-in-contact that is very easy to plug in on the passenger side on the car. You have to take the big plastic cover, under the hood, off to see it.



I've also replace the wires to both ETA and next week I'm planing on rewiring the two MAF's too. They where all cracked up.
PM me if you would like more pics. of that.

Good luck!

benzO320

Ya, i recently replaced the wiring harness on me E320, the only hard connectors to reach were the ones connected to the tranny and by the linkages and a few that you need to hit from the bottom of the car, but the s classes may be different. all mb engines are complex nonetheless

AMGV12

Thanks Jonathan, the harness on top that goes to the injectors are the easy 1’s and I C how 2 get 2 them. It’s the harness that connects 2 the MAF that goes under what I think is the computer plug in on the passenger side (that big black box with the wires going under it) that I have the problem with. My car is running real rich and is smoking from the exhaust. I C where the previous owner took the car a Mercedes Benz Dealer in PA and they so called did a wire fix and U should C the job that these fools did. Instead of replacing the wire harness they tried 2 tie into the existing harness and made a mess of everything. So now it’s up 2 me 2 replace the whole thing. I plan on trying 2 do this myself so your info on this would be appreciated. Thanks again

Jonathan Wallin

Oh. I thought you mean the injection harness. Often called "engine harness".

I didnt know that there was a harness to the MAF's?
I have bought cables to rewire with.

I dont know how to lift the module box to get to the bottom of it.

Is this your plan? To lift the module box and connect the wires in the bottom of it?

This is'nt what I had in mind. I'm planing to solder my new wires on to the old ones near the module box where the cables arent cracked any more any finally cover them with a protection hose.

I would much more like to lift the box if thats possible and replace the entire wire.

AMGV12

That's the problem that I'm faced with. I may have 2 let the dealer do it or get 1 of their best mechanics 2 do it on the side 4 half the price. That's my plan 4 next month. I had 2 get a new Monoblock Rim in chrom(the other 1 was cracked) this month and it was a pain in the @ss 2 find a 19". My plan is 2 do things month by month 2 stay on top of things if possible. I'll let U know what went on with my re-wire, cost and all.

Jonathan Wallin

Today I took a look at the MAF-wires that goes to the box.

I dont think I'll try to rewire the whole length in to the box.

Before the MAF-wires goes into the box they goes into two other thick harnesses. Collected they goes into the box as a VERY thick harness. They are held together with some (stock) tape.

I can imagen the effort to rewire the whole length.

I think I'll follow the MAF-wires to they're not cracked any more. There I'll cut in and solder the new ones in.

I'll post you pics. of it later next week.

I'm looking forward to see pics. from your rewiring.

/ Jonathan

Jonathan Wallin

The MAF-job is over!
The glued contacts are trying so tomorrow I'll start her up. Hope everything is done right!!!

This is what one of the MAF-contacts looked like inside!!!






New cables:




Done!

AMGV12

So did U have 2 lift the computer box near the fire wall on the passenger side, and if so how difficult was it. I thought that the new harness would have come with the MAF connecters attached how long did the job take. Thanks for the pictures and the update, I'll be ordering my harness on the 18th of this month and hopefully have it installed by the end of the month.

Jonathan Wallin

It took one day to do this and I didnt lift the box.
It looked too difficult to do.

I didnt buy a new "harness". I ordered heat resistant cabel and rewired with.
Pooped the contact and then clued it together again.

BUT!
The rough run remains and I guess the passenger side LMM is broken.
I'll have the car in to a MB-dealer this monday for a diagnouse.

AMGV12

I thought about going that route but I was worried that the wires would be deteriorated further down in that bundle that goes under that box. So I’ll just do both right and left engine harnesses as well as the center harness.