Main engine wiring harness rebuild

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Mercedes main engine wiring harness rebuild for S class, SL class, E class, C class

We all know that all 1992 to 1995 S-class and SL-class, 1992-1996 E-class, some C-class Mercedes cars have a major problem: biodegradable wiring harness insulation. Wiring plastic insulation flakes off on main engine wiring harness and throttle body harness, wires short and cause all kinds of electrical issues.

This problem is not only inconvenient but also dangerous. When insulation shorts, engine can stall and could or could not restart. That happened to me on intersections twice and once on the highway. I’m sure you don’t want to be stalled in the middle of intersection with cars approaching. Shorting wiring harness is most probable cause. I can rewire V8 and V12 main engine harnesses. I can rewire other models but it might not be very cost efficient. Read below.

When I bought 1992 500SEL it was in non-driving condition. I bought it cheap to restore as body and interior were in pristine condition. One of many problems on that car was deteriorated and shorting wiring harness. Dealer wanted over $900 for it. It was too expensive for me at the moment and I opted to rewire it myself. I also patched one on my 1996 E320 by taping wires that run to fuel injectors, coils, engine temperature sensors, camshaft advancer, etc. On 92 500SEL I used heat resistant wiring, heat shrink tubing, friction tape, epoxy glue. The job was very labor extensive and took me around 8 hours. Some plugs could no be saved as plastic was very brittle. Metal contacts were reused and new wires soldered directly to them. Finished harness looked close to factory and worked without any flaws. Rebuilding it myself saved me a lot of money. It was on the  car for more than a year and it never gave me any problems or “check engine” light. Sold the car and new owner never had any issues with it as well.

If your car engine stalls, runs rough, misfires, “check engine” light comes on, lots of trouble codes stored in computer memory, wiring harness insulation falling apart, your mechanic tells you to replace wiring harness-rewire or replace it. It’s not only inconvenient but dangerous when car shuts down in the middle of intersection or loose power entering highway.

As of 2014 rewire prices are as following:

92-95 S420, S500, E420, 300SE, 400SE, 400E, 500SL, SL500- $650 shipped in USA

93-95 E320, C220, C280, S320- $950 shipped in USA

93-95 top injectors harness only SL600, 600SL, S600, 600SEL-$650 shipped in USA

96-up- please contact me with vehicle model for a quote

Engine harness rewire is very labor intensive process. Some harnesses have around 400’ of wires to replace. Given that I replace one wire at the time to eliminate possible errors and maintain original wire length for all plugs reach their destinations. Some harnesses take me full day to rewire and some take four days, depending on the model.

Before considering rewiring of your existing harness check with local dealer or online for a price of new replacement harness. In many cases new replacement harness is not much more expensive than rewire and would make more sense to purchase new harness. For some customers it makes sense to rewire and for some it makes more sense to buy new one. I have many international customers where conversion rate is in their favor. Some customers with AMG or Brabus tuned motors, where new replacement harness costs way more than rewire or NLA, preferred to keep original harness. And some customers can buy replacement harness for just a little over my prices.

Aftermarket harnesses are cheaper than dealer parts but they can be revised versions that might have different pinouts and might not work right. If you want to buy new harness, I would order it from dealer according to your car VIN number and double check part number on your original harness. I rewire your original harness one wire at the time so there is 100% fitment guarantee.

When your harness is received I will get to work on it same or next day. Turnaround time is around 1-2 weeks depending on your location and vehicle model. When harness is rebuilt, customer sends payment via PayPal or credit card and I mail the harness back. And if you’re local, you can bring your car to me, I will remove the harness, rebuild it, and install it back into your car for a small fee. I’m in Brooklyn, NY 11204.

Please contact me to discuss repair details.

Best regards,