I've set fire to my car

[Jona1971]

Brilliant, thanks. What's it for?

[Jona1971]

I'm only asking as the same green/black wire heads off in the opposite direction towards the loom in the left hand footwell.

[daimlerman]

Any ideas?

Thanks.

Brian will shoot me down in flames for this,but it may help us all to understand a little more!

Green is ign switched.So your green/black is live with ign on.
Black is starter signal.
Brown,of course,is earth.

So at a wild guess,that plug is to with the start inhibit circuit.....

[Brianmoooore]

Only 3/10, I'm afraid, Malcolm. You're right that brown is earth.

The black wire in the plug connects to a green/purple wire at the ECU loom, and this wire goes to pin 13 of the C101, which is the fuel pump supply. It connects to the fuel pump output because that gives a 12 volt + supply ONLY when the engine is turning.
The brown wire connects to pin 33 of the ECU, which is an earth, looped through from another ECU pin, which is actually earthed.
The black wire changes to purple at a soldered joint near the gear selector, and the purple and brown go down through the floor and to the gearbox, where they power an internal solenoid valve. I have no idea what the purpose of this valve is.
The green/black in the mystery lead goes to a black/brown in the engine loom, which goes to pin 42 of the ECU. The green black goes straight past the selector assembly, follows a mirror path on the LH side of the car, and eventually ends up at an unused (in every M40 I've seen) single pole male spade connector, behind the glovebox area. Since the pinouts of the M40 ECU seem to be a state secret, I have no idea what pin 42 of the ECU is for, and consequently have no clues as to what the whole wire might be for.
The start inhibitor wire is also green/black, and is part of the same loom as the green/black above, along with a different brown earth wire, on the LH side of the car.
The power for the selector position bulb comes from the brown earth wire just mentioned, and from the green/yellow reverse light switch supply. The green/yellow supply also powers the starter inhibitor switch, as well as the reverse light switch, of course.

[Jona1971]

[Jona1971]

" The black wire in the plug connects to a green/purple wire at the ECU loom, and this wire goes to pin 13 of the C101, which is the fuel pump supply. It connects to the fuel pump output because that gives a 12 volt + supply ONLY when the engine is turning. "

- Can I isolate this wire with a switch as a means of theft security? i.e. will it disable the fuel pump?

Thanks.

[Jona1971]

I now have both the dashboard and the body loom and they are ready to install. Small problem:

This is my body loom plug...



...and this is connector to my dashboard loom...



Er, it doesn't fit.

I'm thinking the best solution is another dashboard loom with the correct plug. Any ideas?

(The WIKI says they're all the same, so this may need revising)

[Jona1971]

This is the old one, I need one like this (but in better nick, obviously)

[Jona1971]

Hello again. Right, some progress...

The new body loom is now in the car and needs connecting up. Slight issue is my new loom doesn't have a C101 plug so I'm splicing in the old one and have some wires left over. I have so far soldered:

Green/Yellow to Green/Yellow
Black/Yellow x2 to Black/Yellow
Blue x2 to Blue
Blue/White to Blue/White
Purple/Red to Purple/Red
Green to Green
Brown/Purple to Brown/Purple

I have one black wire left over on the C101 plug and 3 wires left over on the new loom, which are Blue/Yellow, Purple/Green and Black/Brown.

Any ideas which to connect up?

Secondly,

I have a plug that goes behind the bulkhead/skuttle. I think its to the wiper motor. How do I get access to that so I can replace it with the new one?

Many thanks Gurus...
(Getting there slowly).

[Jona1971]

Update - it lives!

Just been for a drive and (mostly) all ok.

I've even saved time by not fitting these...



Seriously though:

The first one, I've no idea where that should go, car is fine without it.

The second one, Brian has explained fully. However, there was no socket next to my ECU to plug it into. My original loom didn't have this fly lead either. There is now an issue that the car, which is automatic, will start in any gear - I think some of these wires need connecting somewhere (in the Left hand footwell) to prevent this from happening.

Minor issues really compared to the fact that BMW designed an awesome car if a donkey like me can rewire it.

Thank you Zone members for your contributions with parts and help along the way.

[TriggerFish]

The big black one is for the check control panel in the roof panel

Glad to see it lives again though - a mistake you'll not make again I'm sure!