1994 E420 - How can you tell if wiring harness has been replaced?
 

Will ALL 1990s W124s need to have this done? Or only certain years and models?

How can you tell if it has been replaced or not?

Thank you!

Looking at '94 E420, just want to be educated.

Thank you!

The 1993 to 1995 need to have it done. You'll need someone with an experienced eye to tell you; I'd suggest you find an MB only independent around and slip him a $20 and ask - was this done? Are you 100% certain?

I am experienced mechanic and would probably be able to tell by comparing photographs, right?

Anyone have a photo of an updated wiring harness they can post?

Thank you!

There is a tag with the date on it right as it goes through the partition on the right side of the engine compartment.

There ya go! Did not know that.

I don't think that's a production date. Seems to me I read that was a design date, which wouldn't really tell you anything. I wouldn't replace a 119 motor wiring harness without signs of a problem. They are not that bad - nothing like the 104 HFMs.

Agreed. I happened to get an early M119 with a bad harness, but my understanding is that the failure rate is far lower for the 119 than for the 104.

Great information guys!

Thank you so much!

Just opposite here. The harness on the 400E crumbled before 100K, whereas, the harness on the E320 still appears to be as new with 133K. Go figure.

85MB300D,

the V-8 M119 wiring harness ALL GO BAD!! 500e500, 400e420

Been there and done that.

they are expensive and do need to be replaced. the heat and cheap materials destroy them.

there is also a lower one that goes bad too.

the only reason there are fewer of these that go bad is that there are fewer V-8's.

http://www.500ecstasy.com go to M119 section and research this

peter

Look at the wires where they are exposed at the temperature sensor in the thermostat housing. Poke at them with a screw driver. If the insulation crumbles you know.

I'll disagree with ALL of the above - just for sport.

First of all not all 119 motor wiring harnesses go bad - a lot of cars make it to the salvage yard with the original, and many more will. This is not to suggest that they are high quality parts but they last longer than 104 HFMs for two reasons - they aren't exposed to the extreme heat of actually being routed into the engine as with the HFM 104s, and secondly it is a much less extensive harness and there is considerably less need to disturb it. 104 harnesses have to be disturbed at the spark plug cover for head gasket repairs and even just to change spark plugs. This causes failures at that most heat exposed portion of the harness. 119 don't have head gasket failures and it is not necessary to disturb the harness to change the spark plugs. So the harness can keep chugging right along even with insulation in pretty sad shape.

119 motor harness aren't that expensive - $400 to $500 if you shop around, and installation is no-cost DIY. This is not that big a deal compared to head gaskets, new trans., evaporators, throttle actuators, and even 104 wiring harnesses.

I've heard of failures of the lower harness but it seems to be less common. I've had four 124/119s and never had a failure or even a sign of deterioration. A lot of these originals are going to make it to the salvage yard too.

What goes on at a 500E forum isn't likely to be germane to the real world.

The point is you don't have to replace a 119 wiring harness just because it's original - it might well make it to the salvage yard, which could be next week given the market value of the cars. Backing into a light pole could total it. You don't want it to show up at the salvage yard with a bunch of shiney new parts.

why are you bustin on me for trying to offer another consideration to
85MB300D??

i'm sharing my own personal experience with the M119.

just because you didn't have a problem, does that make it that way for everyone?

consider these http://www.500ecstasy.com/forums/search.php?searchid=78144

My wiring harness lasted over 225,000 miles. Actually, nothing went wrong with the car, electrically, but once I finally checked the insulation, I noticed it was completely shot.

I still had the original harness and I noticed that there is a rubber sleeve on the new harness, near the lever-type connector, that does not exist on the original. I think the new harness was purchased from mercedesshop. This may be a long shot, 85MB300D, but if the harness on your 420 has the rubber sleeve, maybe it's a replacement. On the other hand, if it was replaced with a factory part, maybe you wouldn't see the sleeve.

He is "...bustin on you..." :rolleyes: because you made a blanket statement that the M119 wiring harnesses ALL go bad. That is not true. All of them do not go bad.