Electric maze... help!

[eddie124]

Hi all,

The biggest contrast by far from my other cars is the electrical system, and to make matters worse I've been removing an old alarm setup from the Tourer. I've now got it all out, but there are a few loose connections that I need to identify and tidy up all the loom. Here's the ones that are really bugging me:



The one in the red circle (thick yellow/red wire) is always live independent of key position, should it be plugged into something?

The one in the green circle (one green, one green/blue iirc) has one terminal that's live when the key is switched on, and the one in the blue circle (thin brown and violet/red) has no live leads, but I've traced this one (by accident) to fuse #28... so maybe it's an accessories plug?

By the way, what are those massive connector blocks in white? I'm not used to having a car whose wiring diagrams span a whole chapter... my classic Fiats have it all in one A4 page...

Thanks for your input on this!

Cheers, Eddie

[Brianmoooore]

Wire in the red circle is red/yellow not yellow/red (although I can't really see it in the pic.)
This distinction is important, as the wire colours aren't chosen at random, but to a code.
A wire with a red main colour, in the body looms, will always be permanent live. This particular one comes from fuse 28, and is probably the feed to the electric aerial on any E30 other than a touring.
The ones in the green circle appear to be the immobiliser socket, and with nothing connected here your car should not run. There should have been a plug connected to this from your old alarm.
If you are lucky there will be a plug to fit this socket taped up to the loom nearby, which is fitted with a short loop of green wire. Cut/pull this plug loose if it's there and fit it to the socket.
If it's not there, cut the plug off of your alarm wiring, a couple of inches from the plug, and join the two wires together to form a loop.
Moving on to the blue circle, plain brown is always earth, but AFAIK, there's no purple/red in the area, and certainly not one connected to fuse 28.
Blue/red, I will believe, and this is the connection to the indicator repeater on the LH front wing.
The big white socket is the accessories socket as you surmise, and is for things like the radio, ABS, cruise control, central locking, heated seats, etc., several of which you appear to have.

[eddie124]

Hi Brian,

Thanks for that!

Indeed, the big wire is red/yellow, not yellow/red, silly me! Is it meant to plug to anything? Seems kind of hazardous to have a live feed hanging there doing nothing... or should it simply be capped?

I was wondering about the green ones (solid green, btw), as they connected to a plug in the alarm (plug itself was BMW original) and it had two short bits of green but no apparent destination in the harness... so they're meant to be a loop, right? Makes sense.

The third one is indeed blue/red, not purple/red, and brown. Why is this one separate from the rest and hanging here? There seem to be no similar connections in the area, that's why I wouldn't associate it with anything similar to an indicator.

By the way, it seems a few of my diagrams do not match the actual colours present in the wires, so maybe they're an older/newer version? I have a digital-format Haynes workshop manual, but it spans E28, E30 and E34 models, so that could also be an issue. Do you know where I can find the correct wiring schematics for my Touring?

Sorry about the bunch of questions... still trying to navigate through my first "modern" car...!

Cheers, Eddie

[daimlerman]

Indicator repeater feed is unique to RHD,it forms part of the dash harness,that's probably why it's just hanging about! Should be a matching socket coming into the car behind the radio speaker,from the side repeater.
Best manual,BTW,is the American Bentley one,once you get your head around the American way of speaking/writing!
Interesting collection of 'Fix It Again Tomorrow's';Any photo's?

[Brianmoooore]

The end of the red/yellow should just be hanging there, but it should be fully enclosed by plastic, to form half of a plug and socket pair.
Green needs to be made into a loop.
Indicator repeater as daimlerman says.
Best wiring diagrams by far are here: http://www.autolib.diakom.ru/CAR/BMW/
Just click on the drop down boxes.

[eddie124]

Thanks guys,

I've now got that sorted, but grabbing hold of the wiring diagrams, I started testing out a few other issues like why the power windows and sunroof don't work.

This led me to the power distribution box, but I'm a bit stumped because the relays all seem dead! Is this normal?

Also, by the wiper control unit there's another relay that I can't find in any diagram, but it is wired and stays on all the time. Any ideas on that one? It sits right besides the wiper control, apart from the other 8.

Is there any particular feature about these relays or are they off-the-shelf items? I've noticed by the schematics that one or two are switching relays but the others seem normal. If so, why are they all dead? If I try to feed them, they don't click on. But the minute I insert a regular relay in their place they switch right up!

I think I'm going to have a good look at the underside of the power box, because there's a lot of weird stuff going on in there...

Cheers, Eddie

P.S.: Daimlerman, my webpage button takes you to my 124 Spider's journal, and on that you'll find a link to my other journal, with the 2100's restoration. But please don't call them that... they're not plastic rubbish like the 80's junkyard fodder. In fact, I'll take them over a 60's beemer anytime! They're brilliantly engineered machines.

[Brianmoooore]

Relay by the end of the wiper module is K9, and switches power (ignition switched) to the rear wash/wipe.
All the orange relays are simple single pole normally open types. All can be bypassed by linking together 30 and 87 of their sockets.
Heater fan, mirrors, windows/roof all receive their power via one of the two unloader relays, K5 and K7. If these aren't working, the usual problem is a fault with the black/green wire going to the smallest terminal on the starter motor.

[eddie124]

Hi again Brian,

Many thanks for that clarification, I did suspect it would be something like that, unique to the Touring!

I still need to figure out why that K9 is permanently on, though... I suspect something is definitely amiss underneath, or I misplaced some other relay, it could happen!

Will have a look at the wire on the starter tomorrow then.

Cheers, Eddie

[Brianmoooore]

One side of K9's coil (pins 85 and 86) is earthed, and the other side is connected to fuse 6, which should only be live with the ignition switch on to at least the first position (purple wires).

[eddie124]

Well I've made a bit of progress. I forgot to mention that I'm between engine looms right now, as if you remember my Tourer had a pre-facelift engine and loom put into it but it never ran. Silly me, it had never ocurred to me before that big-consumption items like power windows would be run on a more direct feed from the alternator/battery lines.

Mark (town325i) kindly provided the bits for the engine's conversion to facelift loom but DHL fumbled the delivery and they're still in transit as we speak, so my engine loom is not there, hence no feed from the starter terminal to C101 plug, and no juice for accessories.

One thing that was bugging me was why the old relays didn't click on and the new ones gave weird symptoms... that's when I found that BMW items have terminals arranged in a different position to my conventional relays (I'm used to switching terminals being arranged either side, but BMW items switch from the top to one of the sides). So now everything is back together and awaiting the engine loom.

Brian, could I plug a feed direct from the battery to the terminal on C101 to check the operation of these accessories? If so, which terminal (on car loom side) corresponds to the black/green wire you mentioned?

I'm just trying to get everything checked and back together in the interior (dash being swapped as its top was cracked and so I'm taking the time to get all the electrics sorted, removing the old alarm and other stuff) to use my free time until engine stuff gets here.

Cheers, Eddie

[Brianmoooore]

You don't need to connect power to the black/green - you need to earth it.
It's pin 15 on the C101.

[eddie124]

Brian, you're an ace!

Earthed pin 15, and hey presto! I've got windows, I've got sunroof... no more dingy air to bear through while working on the dash! Now I can have it open to see if it loses that awful smell when the weather's nice (we were having 35 deg C days last week, but now we've been tasting rain and cold again... so much for global warming!).

Now to finish descrambling all those loose stereo wires so I can refit the dash. At least this keeps me entertained while Mark's engine bits don't get here.

Cheers, Eddie