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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, 1994-1996 C-class Mercedes cars have major problem: biodegradable wiring harness insulation. Plastic insulation flakes off on main engine harness, throttle body harness, starter/alternator harness, Mass Air Flow meter harness ( V12 engines) . Wires become exposed and short together causing all kinds of electrical issues.

This problem is not only inconvenient but also dangerous. When wires short 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 engine to stall in the middle of intersection with cars approaching.

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. Back when I bought the car dealer wanted over $900 for it. It was too expensive for me at the moment and I opted to rewire it myself. On 92 500SEL I used heat resistant wiring, heat shrink tubing, friction tape, epoxy. 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. 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. I also patched one harness on my 1996 E320 by taping wires that run to fuel injectors, coils, engine temperature sensors, camshaft advancer, etc. but it was temporary repair.

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 2015 rewire prices are as following plus shipping cost:

92-95 S420, S500, E420, 300SE, 400SE, 400E, 500SL, SL500- $1100

93-95 E320, C220, C280, S320- $1500

93-95 top injectors harness only SL600, 600SL, S600, 600SEL-$1200

Mercedes C36 AMG injector-$1800

Mercedes C36 AMG transmission harness-$400

Mercedes V12 Mass Air Flow sensors rewire on car in my shop-$1500

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

Other Mercedes or Non-Mercedes harness- please contact me 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 to reach their destinations repair takes very long time. Some harnesses take me one day to rewire while others take days depending on the model.

Before considering rewiring of your existing harness check with local dealer for a price of new harness. In some cases new harness is not much more expensive than rewiring and would make more sense to purchase. 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. Customers with AMG or Brabus tuned motors, where new replacement harness costs way more than rewire or NLA, prefer rewiring and keeping original harness.

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 couple of weeks depending on vehicle model and mo shop workload. When harness is rebuilt customer sends payment via PayPal or credit card and I mail the harness back. Customers are also welcomed in my shop where I can remove, rewire, and reinstall your harness.

Please contact me to discuss repair details.

Best regards,