Who has done a custom chassis wiring harness?

[JFarhanbod]

I'm pretty sure I fubar'd my interior wiring harness when trying to remove some of the wiring for electronics I removed from my car and to be honest, I don't even want to try and diagnose the problem. The car has been through some shit (80/90s electronic installations). So I'm thinking about just doing a custom wiring harness. I'm just keeping the bare minimums. Horn, Turn Signals, Wipers, Headlights/Fogs, Aftermarket Gauges, Mini Amplifier, Windows and Doorlocks.

Original plan was to pick up a painless wiring kit but as soon as I saw the price of those, I changed my mind. I found this company called EZ Wiring and they have a kit called the mini 20 that looks like it would work for me

http://www.ezwiring.com/wiring_harness.html

My question is what is involved to switch to a custom wiring setup? It seems sort of easy to me but I might have the wrong idea or something.

Just run each wire (they're labeled) to its accessory and for the ones I need switched, just wire a switch between it. Is that it??

Also is there any way to retain the stock cluster? I would rather keep it but if its too difficult, I will switch to gauges.

And do I have to tie in the motor harness with the chassis harness?

This is all for my e24 but its basically the same thing as an e30 and anythings thats different, I can usually figure out its equivalent.

Thanks!

[AndrewBird]

This is much more complicated than you think. Yes, the engine harness would need to be tied in. It runs to the fuse box and get power there, plus runs to things like the cluster and OBC.

Your best bet would be to get a used e24 harness and swap it in. WAY less work than going custom.

[JFarhanbod]

This is much more complicated than you think. Yes, the engine harness would need to be tied in. It runs to the fuse box and get power there, plus runs to things like the cluster and OBC.

Your best bet would be to get a used e24 harness and swap it in. WAY less work than going custom.

Unfortunately, finding another e24 harness is harder than it sounds and then at the end of the day I'm still left with a bunch of connectors and wires that go nowhere.

What makes it more difficult? If anything it seems tedious but thats fine.

I dont really plan on using any of the electronics, my car no longer has an obc, check panel, abs, ac/heater, etc.

I really just need the bare essentials as this car is basically becoming a street legal track car. Oh I forgot to mention that I'll be switching to megasquirt soon if that makes the install harder or easier

[AndrewBird]

Basically it's just a matter of running all the wires to every component, but the way the factory wired things might be different than how your "kit" comes, so there is still a lot of custom wiring that needs to be done. Basically if you can't wire the car without a kit, you likely won't be able to do it with a kit. Having the proper tools to terminate everything is also another thing. Decent crimpers can get expensive.

The fact that you removed a lot of things will definitely make things simpler though. If you have a firm grasp on car electrical systems, you shouldn't have a problem, but if you are even a little shaky about it, I wouldn't attempt it.

I would start by making a list of everything in the car that needs to be wired. This will give you an idea of how much wiring there will actually be.

[JFarhanbod]

Basically it's just a matter of running all the wires to every component, but the way the factory wired things might be different than how your "kit" comes, so there is still a lot of custom wiring that needs to be done. Basically if you can't wire the car without a kit, you likely won't be able to do it with a kit. Having the proper tools to terminate everything is also another thing. Decent crimpers can get expensive.

The fact that you removed a lot of things will definitely make things simpler though. If you have a firm grasp on car electrical systems, you shouldn't have a problem, but if you are even a little shaky about it, I wouldn't attempt it.

I would start by making a list of everything in the car that needs to be wired. This will give you an idea of how much wiring there will actually be.

I have a pretty good idea about the cars electrical system and my father is an electrical engineer so he has taught a good amount about electrical system in general although car wiring is a bit foreign to him.

I have greenlee crimpers but my pops might have something better in his arsenal.

The only thing that has me shaken up a bit is having a no start situation. What are the main things on the chassis harness that allow the car to start?

Here is pretty much everything I'm planning on keeping

Horn
Turn Signal (stock)
Hazard Switch
Wipers (toggle switch, max power)
Aftermarket Gauges (Power, Ground)
Stock Cluster (if possible)
Aftermarket mini amp (connect to radio fuse)
Lights and fogs (toggle switch)
Brake Lights
Reverse Lights
Cig Lighter or USB port
Door locks (use aftermarket viper alarm/keyless entry if possible)
Windows
Ignition switch (stock)

[JFarhanbod]

Alright, I went through the ETM and I'm going to try to splice things that work properly (ex. Central locking) into the new harness.

Anyone know if the stock cluster would work?

[Farbin Kaiber]

Looks like many hot rod style harness kits would wire exactly what you want, just keep connector ends to have factory connectors for the BMw specific connections you'll need to make. Think Painless, Rebel, etc. There are lots of bare bones kits that would do what you want, and shed some weight I'd bet.

http://www.ez2wire.com/500695-HIGHWAY-22-PANEL-WIRING-KIT-complete-panel-and-full-wiring_p_4166.html

But, is it easier than pulling a stock harness and putting it in? Nope.