wiring harness question...

[gooseadrian]

I want to know how hard it would be to remove the complete wiring harness and remove any unneeded circuits all the way down to the ECM. Thinking about doing this to clean up all the wiring around the car but want to know how difficult it would actually be.

[jlevie]

If this is a street car there is very little unneeded wiring. However, if it is a race car there is a lot that can be removed. While not terribly difficult to do, it is a very tedious process. You have to identify what still has to work and then identify the wiring necessary to accomplish that and remove the rest. Or you can remove everything and run new wiring for just what you need.

[ross1]

If this is a street car there is very little unneeded wiring. However, if it is a race car there is a lot that can be removed. While not terribly difficult to do, it is a very tedious process. You have to identify what still has to work and then identify the wiring necessary to accomplish that and remove the rest. Or you can remove everything and run new wiring for just what you need.

^ yep, emphasis on tedious. LOTS of wire and weight* in the car but little can be removed and still have a fully functioning road car.
* 70# + in an E34

[gooseadrian]

So not too hard, but very tedious...doesnt seem too bad.

[TobyB]

Actually, if you don't mind half- measures in a race car, there's a lot you can lose
for a limited amount of work.

The windows, the door locks, cruise and a few other 'add- ons' get their own wiring
harnesses- once you sort them out, it's easy to pull them and get down to the base
harness. Once you're there, there are some wires you could ditch from it, but
THAT is a bunch of work. For a limited (5# maybe?) gain.

Since I wanted functioning lights and stuff on the car I'm building, I 'reused' a lot of the
unneeded circuits in the main harness for racing things-
so the rear brake sensor became the diff temp sender, the A/C compressor wire became
the power for the transponder, etc etc etc.
It took a bunch of time, but it turned out pretty cleanly, and was fun.
As a bonus, I now know most of the ETM by heart...

t

[Jaxx_]

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/473807_1750928498368_1393531107_31509014_636776311_n.jpg

just did this on my car. I'm still not done, but probably lost about 3-4 lbs already. This was only the dash harness removing everything except for hazard(but it was shorted to the factory fog light switch placement). Still need to go through and do body harness, as well as removing preinstalled wiring for factory options, such as OBC/Cruise control/etc. Not to mention, power windows and other wiring. Door switches for interior lights and even door buzzers. There are many things to eliminate still.