1992 300 se



Hey there,

My buddy’s got an electrical problem with his windshield wipers. The fuses and motor are fine, but the mechanics he’s talked to say that there’s a faulty wire that needs replacing. Everyon he’s talked to says that the wiring is under some sort of metal chassis, and that the labor of getting in there to work bumps up the labor costs. He’s got someone willing to work on his car, to replace this wire, for $75. Does any of this make sense? Is he getting taken to the cleaners? How easy would it be to DIY this?


A 1992 Mercedes has definite problem with a degrading wiring harness. A very well known issue caused from using an insulation that was supposed to degrade when the car made it to a junkyard after life. The problem is the harness degrades many years too soon, causing all sorts of electrical gremlins to come out of hiding. Many more electrical problems are on the horizon unless fixed.

The only fix is a replacement of the factory harness with an updated version.

When the problem first arose many dealers simply replaced the harness with a new degradable one, meaning of course, the problem will come back eventually.
Make sure you specify the updated non-degradable harness.

This is a very well known repair on these cars, and shouldn’t break the bank. The updated version should resolve the issues from here forward. No need to go to a dealer for the repair. Any Indy who knows Benz’s can do it easily.



Arlen, you and Benzman may be talking about different wiring. Is your buddy experiencing any other issues on his SE, or are faulty wipers the only symptom? It’s true that '92-'95 Mercedes (and other European manufacturers) had environment-friendly, degrading wiring harnesses, but nobody who knows what they’re doing is going to replace the harnesses (there is more than one) for $75. Even if your buddy only replaced the main cable harness (that’s the one that connects to the wiper motor and about 100 other places), that’s a big job, and the harness itself is VERY BIG $$$.


We’re not talking about different wiring. The insulation on the wiper assembly is subject to degrading, as is all the other assemblies on the harness. Electrical gremlins will start to constantly arise now that the insulation is crumbling and exposing wires.

No, fixing the one wire to the wiper for $75 will not fix the overall problem. The entire harness needs replaced. At a dealer the job runs around $1400. Many, many factory harnesses have been replaced by Mercedes Benz under a little publicized factory campaign.
The issue never fell under a factory recall however. Speak to the Mercedes regional zone representative and ask for factory help. Mercedes may well step up to the plate.