Need help figuring out these wires

[Galro]

Hello again.

As I said previously I am trying to get my old BMW e3 in working order. The car has stood dormant and partly dismantled for years, which has posed a problem given that I don't really have that much knowledge about it. One of the issues I have is with the electronics. More specifically in the engine bay (also some in the interior, but I will focus on that later) where there are a bunch of wires and cables that hang loose and which I don't really know where they are supposed to go. I was therefore wondering whether someone here could help me figure it out?

The lighting is kind of poor here and my phone is struggling to focus on the thin wires, but hopefully it is possible to make out what we are looking at here.

I have circled where the loose wires are:



The wires in the red circle. I thought that this was maybe the ground for the headlight assembly, but I can't for the life of me manage to attach it to the loose wire that comes from the headlight bulb (as far as I can tell it don't fit at all). I also can't see anywhere else where it could go. So what gives? If they are supposed to attached together, how do you do it?



The wire in the green circle. I think this is perhaps for the washer fluid system that are attached to the hood, but I just wanted to be sure.


The wires in the blue circle. The situation here is basically the same as the first set of wires - to me it looks like the ground and it looks like it is supposed to be attached to the headlight assembly, but it don't seem to fit. I also can't see any other places where it could be attached.




As said the pictures aren't the greatest, but hopefully it is possible to understand what we are looking at here.

 

[bavbob]

Someone hopefully will have a wiring diagram to share. Buy a multimeter. Brown is always ground.

 

[HB Chris]

Green looks like it goes to the coil as it is switched power. Yellow is low beam, white is always hi beam, ground is always brown.

 

[HB Chris]

We need to know what year?

 

[HB Chris]

Green/yellow is horn, green can be turn signal along with blue. We also need to know US vs Euro E3.

 

[Galro]

We need to know what year?

It's a 1974 2500 Euro model. It have a engine fitted from a 3.0si though. The work wasn't been done by me so I don't know what kind of modifications were done to the electronics at the time.

I can take more pictures tomorrow if it is of any interest.

 

[HB Chris]

The blue books have diagrams by model and destination.

 

[Galro]

The blue books have diagrams by model and destination.

Are you thinking of the Kelley Blue books? Or are there are other car related blue books that I'am not aware of? Unfortunately that's not something I have access to. I do have however a Haynes manual with some some electrical diagrams in it (it's for a UK market car, so I'm not sure how similar they are). But I no knowledge of the field and I don't really understand what I am looking at there. I could perhaps scan them and post them here and maybe someone else could make sense of it?

 

[HB Chris]

This Blue Book. I will check some of the wire colors for you.

 

[HB Chris]

This is for a euro 2500/2800/3.0S/3.0Si:

Left turn signal blue/brown, right turn signal blue/violet plus brown for both
Horn green/yellow plus brown
Lo beam with parking light yellow/black for main filament, green/yellow for city light plus brown
Hi beam white/violet plus brown
Horn relay by battery brown/green, green/yellow, violet/black, red
Hi beam relay white, white/violet, brown, red
Ignition coil green to ballast resistor then black/red to coil (2), black (2)
Voltage regulator to alternator black, blue, brown plus large red from battery to alternator

Hopefully this will get you started.

 

[Galro]

Here is a also close up of the wiring I am looking at on the left side (red circle above). It's yellow/black wire on the left that I need to attach to something in the other end. Surely this have to be the ground, as it only appears to be attached to the body here? And I guess based on the "colour chart" above, it is supposed to connect with the low beam?

I also assume the set with wires on the right are for the turn signal (but they are attached)?



The loose wire on the other end have a similar arrangement, but I wasn't able to take any good pictures there due to the poor lighting.

 

[HB Chris]

That plug is part of the emissions system that was attached to the coil, it’s no longer needed

 

[Galro]

That plug is part of the emissions system that was attached to the coil, it’s no longer needed

Are you here referring to the wire on the left? I think you are maybe thinking of the one to the right? As surely the one on the left is not part of the emission system?

 

[HB Chris]

That is not a factory wire or spade terminal, the round plug hooked up to the silver box known as a speed relay below your coil which controlled the dashpots or magnetic switches on your firewall. These affected vacuum advance and retard.

 

[Galro]

But you are talking about that plug thing to the right, right? Or have I misunderstood you now? You don't happen to have any pictures of another E3 and how it looks like there for reference?

 

[HB Chris]

In your last pic the yellow grounded wire I assumed went the the round plug. If it doesn’t someone has swapped out a wire as yellow is Never a ground wire. Did my other wire color suggestions make any sense?

 

[Galro]

The yellow wire is not connected to the round plug. I don't think it is connected to anything at all beside the body of the car. It's possible that it is not original - as said the car have had an engine swap and I assume at least some part of the electronic had to be changed with the engine.

To be honest I haven't looked through the other suggestion yet as I have only focused on this wire.

If someone else have a partly dissembled BMW e3 here, then I would love to see pictures of how the wires are connected at the front of there cars.

 

[Phemisg]

The RHD wiring diagrams should cover many of the areas in question. You should be looking for wiring colours and functions to confirm the wire is original. Brown wires are usually ground; you can check with continuity tester. What you don't want is hot wires flapping around unconnected.
Someone has converted the headlights to aftermarket buckets and more powerful bulbs. I'm not sure why they had to rewire things. Do the lights work?
I'd be getting some seam sealer on the fender welds to keep water out.

 

[Galro]

Hey, sorry for the late answer. I have been a little bit busy so I haven't looked at it more.

I haven't connected it to the battery yet as I didn't feel comfortable doing that without knowing what's up with the wiring. However everything worked at some point (after the new engine was installed), including all the lights. So it should be possible to get it working again with this wiring.