I am cross posting this from bimmerforums.com in hope I can expand my search and some advice.
A month ago my 90' E34 525i caught fire inside the dash. Everything from inside the centre console and driver side are gone. Fire started at the centre console and spread to the driver side. The passenger side is unscathed in the inferno. Everything past the firewall into the engine is also unscathed. So that is that saddest part of things.
I managed to find a donor car and I will have everything needed to fit back the damaged stuff - except the wiring harness. The problem is that the donor is a entry spec 1991 520i. My 525i has check control system, LKM and stuff. The 520i does not. I get loads of 520i here but 525i is hard to come by in my part of the world. I checked my local scrapyard and they don't have any 525i for me to salavage.
From my understanding the main wiring harness for the 520i is similar to the 525i - everything that is plug and play like electric seats upgrades, etc is there EXCEPT the check control system and probably LKM.
Does anyone here knows the key differences and is it possible to run the additional wiring for check control and LKM? I have a feeling if I study the wiring diagrams of the 520i and 525i side by side it can be done. Questions is whether that is the best route to go for now. Or should I go the route to source for a used 525i harness instead? I can see plenty of engine harness out there for sale but the main dashboard harness? Seem to be almost non existent.
Any advice will be helpful.
ps: if anyone got a 525i harness with control system to part. I will be there for your main wiring harness