So unfortunately for me, I discovered whomever did my spark plugs prior managed to damage one of the wires. The plug was also missing the grey tab.



I'll be attempting a complex wire repair instead of replacing the entire engine wire harnass in the near future.

 

I'd take a close look at that damaged wire. If the conductors aren't really damaged (as in "more than a couple strands broken"), I'd just take the connector housing off, slip a piece of heat shrink tubing over the area, shrink it down, and reassemble using your new housing. That will let you get by without having to crimp or affect the wiring in any other way.

 

It has been fine (and no codes) since I've owned the car from 2022. Since it is so close to the terminal, I'm going to trim all four wires back to that damage, strip, and crimp on the new terminals. I've already bought all the necessary tools.

 

I replaced the broken connector today. I discovered the crimp die that I purchased was for the correct terminal size, but not for sealed terminals. So waiting on the proper replacement.





To properly release these terminals you will need W220589019963. I am using a rebranded (and cheaper) Stahlwille 1578K-2. I have not seen any cheaper alternatives on Amazon. The M272 engine uses the same terminals, so this tool can be used for those connectors as well.

 

Ten bucks would get you a can of liquid tape, or 7 bucks for a tube of silicon to seal the damaged plastic.

 

That's what I was thinking.

 

I'd suggested taking it a step further - getting a new connector housing (the old one's latching tab was broken), and swapping the wires and pins over one at a time, putting heat shrink on the one with damaged insulation. IMHO, the fix would have been better and more reliable than a total rework of the connectors and pins, but we all have to make the decisions we think are best.

 

Its kinda difficult to get a good picture but the heat shrink would not reliably seal because the cut extends to the red weather seal. I've already replaced the connector. The new production connector has a white tab versus the older grey tab.

 

Repair complete. No issues reported.

Pretty straightforward:
-Disconnect battery
-remove intake
-I used a cookie sheet to collect debris
-Disconnect harness as far back to ECU from the fuel rail (this gives you more room to manipulate the harness)
-trim harness loom back to desired length
-cut wire and strip to size
-replace single wire seal
-crimp
-put everything back

0.75mm² stranded = 20 AWG Stranded
1.5mm² stranded =16 AWG Stranded





Clean with electronic cleaner and insert all wires to appropriate slots. Replace plastic connector. Adjust zip tie if necessary to increase bend radius on the wire loom to alleviate sharp bend.

 

Well done! I haven't seen much of this on this site, so thanks for paving the way.

Can you please list part numbers for tools and parts (terminal, seals, connector shells), and sources where you purchased them? Thanks.

 

I just purchased the terminals from the Mercedes-Benz Dealer. You can get it cheaper from Mouser or Digikey but the small quantity I purchased was easier through the dealer.

A0095458126 (⌀0.75mm²) + A0005457180 blue seal
A0095458226 (⌀1.5mm²) + A0005457680 red seal
A0005458912 four pin plastic connector for M276



The terminal release tool is W220589019963. It was more cost effective to get one from Stahlwille as 1578K-2.


You'll also need a pair of flush cutters to trim the terminals. Regardless of where you source the terminals, they are manufactured on reels. You need to cut the terminal tail end flush and clean. The Mercedes-Benz supplied terminals are snapped off and they have a noticeable sharp edge; kind of like a poorly trimmed zip tie. This prep work will ensure a good seat crimp of the seal.


Pair of scissors and calipers for measuring. I am using some specialty curved beauty scissors for eyebrows. They are tiny and nimble for cutting into the loom cleanly. I also had a seam ripper but it wasn't sharp enough to cut the loom.



Any can of electronic cleaner.


Good quality wire strippers. I prefer these german made Knipex 13718. The automatic ones are more bulky and I find they don't do a clean cut on tiny wires. The AWG sizes worked in this instance, but may not strip cleanly on other applications depending on the insulation thickness and type.


For the crimp die, you will need W220589019909 or whatever equivelent that is cross referenced. Make sure it is for ELA terminals, that denotes it is for sealed terminals. Wezag in Germany supplies the W220589019910 hand crimpers to Mercedes-Benz. So you can use any of their private label crimpers in conjunction with the crimp die. For example, the BMW crimpers are the exact same just with a different lasered part number 83-30-0-495-324. I found some brand new Molex crimpers for cheap so that is why I have red handles.


This is what the W220589029900 full crimp service kit looks like: (photo courtesy of my dealership friend)