View Full Version : My Upper Wiring Harness Install Thread

12-14-2012, 08:35 AM

So I have a 1992 500e with 167k miles that runs strong. Based on my inspection of the wiring harness, it was clear that it was well overdue for a replacement, as most of the insulation was completely gone and there is no doubt that wires are crossed and moisture was taking it's toll. The ground wire was also very brittle, which I think was causing random rough idle and ASR light issues.

So, I ended up buying a 1993+ upper wiring harness from Parts.com. I cross checked all the components that the wiring harness touches from a 1992 to a 1994 car, and all part numbers were the same. This was the MAF, Injectors, Temp Sensor, Coolant Sensor, Cam Sensors, etc.

So, I am pretty confident that I will have no issues with fitment, but will find out in short order I guess. Attached are some pics of the new harness, will take some more pics along the way of the old harness and install today or tomorrow when I get around to it.


12-15-2012, 11:04 AM
Just completed this job, took about 3 hours being careful. The '93+ harness fit without any issue on my '92. Will upload a couple of pics, but just took it for a ride and all is very well!

12-15-2012, 11:30 AM
Congrats! Just curious, what was the reason behind buying the late style harness for your early car? Was it due to the lower price?


12-15-2012, 01:20 PM
Originally, I misread a thread and thought my VIN was eligible for the later harness. That coupled with the lower price was the driver. Once I ordered the later harness, the parts guy called and said I needed the earlier harness, so I cross-checked every part number that the harness connected to, and found no part number differences in those down-stream components. So, I felt comfortable going with the later harness afterall.

Took it for a good drive today, very happy. Easy install, really just plug and play.

12-15-2012, 04:27 PM
Some pics of the start to finish install. Not sure they tell much of a story, but we all like pics!

12-17-2012, 04:51 AM
Fancy re-upping them as full-sized instead of thumbnails? :)