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Discussion Starter #1
Hello,
I have a 93 E34M5 Touring. I am attempting to sort out all of the wiring issues while I have the car apart. It has been a frustrating experience to say the least. I am experienced when it comes to wiring. I have done many cars; splicing and complete harness transplants. The most important item to have is accurate wiring schematics. The only accurate wiring schematics I have found for my Touring are in German. A fellow forum member gave me a link to download them. I would have been completely lost without them. With them, I have made the following observations about the wiring differences between Euro and North American market cars.

1) Euro cars come with most of the wiring for common options pre-wired into the car. Many of the components are completely different than the US versions. For example: The Alarm system is pre-wired in all Euro M5's. It is called DWA, and has different versions. The North American alarm system is an Alpine. You will not even find the DWA wiring chapter in the US manuals. The towing harness for cars with the factory hitch from Europe have a Towing Module. The US cars do not. The wiring for the US cars that add the option is different plus it is done without adding a module.
2) Euro components are sometimes in different locations. Example: Cruize control computer for Euro M5 is behind the driver's speaker panel. In US M5's, it is in the engine bay passenger's side by the DME.
3) Because of the differences between Euro and US versions, wiring connections to components often have some pins used in the Euro versions that are left blank on the US version.
4) The good news is most of the wiring is about 95% the same. BMW is also very consistent with wire colors. I would say the wire colors are 99% the same. When in doubt with a erroneous pin location compared with the schematic; Go with the wire color...

Now, it really gets interesting when former owners or the importers that are federalizing the car, are unfamiliar with the above, and modify the car using US schematics for the job. This I believe, is where I am at. The dash computer system does not work, and the check control system is problematic. So far, it appears someone tried to modify the towing harness by rewiring it to the US version without a Module when the Euro wiring and Module were already in Place... The upper brake light was just spliced into the right rear brake light circuit, which is wrong in Europe and the US... The US wiring uses the lamp control module for illuminating the upper brake light. The Euro wiring uses an additional relay that uses the lamp control module to activate it. This has to do with the Check Control Module, and the monitoring of the lighting circuits.

Many components identified in the schematics are not listed in component locations. In this case, I can usually trace wiring manually to find the components, but it takes time plus the car has to be apart to get access to all of the wiring bundles. The worst case senario, is when the component isn't listed and the wiring has been changed or removed, so it can't be traced. That is where I am at right now.

I am trying to locate the relay for the third brake light, K107. I think it was supposed to be in the rear aux power area under the rear seat. I can not find it, nor any wires leading to that location. Can anybody look and see where it is located? It will have to be someone with a Euro Spec Car.

Sorry for the long post. Any help will be appreciated.
 

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was a third brake light even an option in europe in the early 90's? Neither of my euro cars had one. My sedan had a rear spoiler with third brake light installed as part of its federalization, and like you say, they just spliced into the brake lights (with speaker wire!). My touring had a US upper hatch spoiler installed with the light, and again, just spliced into the brake lamp.

yes most of the federalization wiring is frightening. My touring had a 'key in ignition warning chime' added, and there are a bunch of extra wires spliced under the dash to make that work.

If you could post up the euro touring wiring diagram link at some point that would be really handy.
 

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FWIW, the BMW/NA ETM are not complete either.
I've done a ton of wiring updates memory seats/steering column/mirror, 17pin head unit w/10 channel Amp, Diversity Antenna, Alarm system, etc. on my M5 and the component may be listed, maybe not, but the chassis location is blank.

I did a quick look at both ETMs Euro vs US.
I also tried the look up the relay K107 connector X18258 trick and nothing.
Nothing in the rear seat power module layout.
F43 is shown in the rear seat relay block.
K107 is most likely installed with an option wiring harness and maybe it is in one of the EBA wiring diagrams?

You should have been around in the paper manual & microfiche days Oh man! was that brutal!!
 

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Discussion Starter #4
The relay K107 may be only present in the wiring harness that comes with the Towing Package. The towing package is referred to as the AHM,(Anhänger-module). I will upload some schematics and look for the link for the German ETM. Thanks for everybody's help.
 

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Discussion Starter #6
Brake Light Schematic from German ETM


This schematic shows relay K107. This is the one I can not find.
 

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the schematic you've shown has KSA listed for the lines leading to relay K107. KSA is Saudi Arabia vehicle code so this option is probably just for cars going there - hence why you can't find any of that branch

My car is a UK 1990 which has no high level light (not many euros did). however, the wiring is all in place for it, but the LKM has no pin for it. Australia has its own version of the LKM which includes all the euro options like fog lights and additionally has monitoring of the high level brake light. I fitted an AUS LKM and it works perfectly.

Like you say, Euro cars tend to have all the wiring in place so I'd suggest it is there. The wiring to the high brake-light should run directly from the lamp itself to pin 15 of the LKM connector.

I can try and find another one at the wreckers next I'm there if you're interested. Doubt they'd want very much for it.

I think that actually the Australian LKM might be a bit of an "ultimate" E34 LKM as it has absolutely every lighting feature enabled.
 

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Discussion Starter #8
Thank you "Konfused Pete". This answers the question of why the high brake light is on a Euro schematic; "It's not for Europe!". All of the North American cars have the High brake light powered by pin 15 of the Light Control Module (LKM), like you said. My LKM has the pin, but there is no wire in the harness. I don't know if the Euro LKM has an active pin 15 or not. It sounds like the Australian boxes might be a good option.

Since I have the towing package, I am going to add a relay like K107, to isolate the high brake light circuit. My understanding, is when pulling a trailer, the Check Control Module would give erroneous light failure messages, because of the change in the light circuit loads. The AHM module and high level brake light relay were added to the towing circuit to prevent the CCM from triggering errors. For me, adding the relay is easier than adding a wire the entire length of the car. Other members that have Euro Cars with the high brake lights without the towing package could certainly use your LKM solution. Thank you for taking the time to solve this piece of the puzzle.
 

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I have a towing package in my garage, but haven't fitted it yet. As the high-level light has its own monitoring circuit in the LKM, I don't think the AHK module (which only taps into the left and right lines) will trip up the CCM by having the centre light as well.

I think your idea of going the K107-esque option should work well for you and, like you say, save you running wiring through the whole car.
 

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Discussion Starter #10
Do you have the factory package that includes the AHM module? I downloaded the installation instructions for the towing package for the E32. The electrical hookups should be the same. Unfortunately, they do not mention the High Brake Light. This does bring up several questions that I had after reading about the tow kit installation. First, the flasher relay is replaced with one in the kit. How do I know if I have the correct one installed? Do you have one in your kit? Can it be differentiated from the stock relay in anyway? Next question concerns the repeater light for the turn signals in the instrument cluster. Evidently the wiring for this function is in place and all that is done to activate it is to place a light bulb in the designated socket. Now my cluster was changed with a US M5 cluster. What are the odds that everything still works? Probably lower than whale dung...

Wow! Sorry about bombarding you with all the questions. Maybe your handle should be "The Shell Answer Man"...:)
 

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the AHM wiring is also in that German '93 ETM if you haven't found them already under 6328. High brake light definitely doesn't come into it because like we talked about earlier, the line for that light comes directly from the LKM. The AHM is fitted in the boot/trunk where there is a breakout connector (thanks BMW) in the tail-light wiring which the AHM taps directly into. The AHM is a mini LKM for the trailer lights which also doesn't load up the main lighting so as not to trip the bulb-out warnings of the main car. As the AHM has its own connection to the check-control system, it probably just tells the car about any trailer lights which are out.

I don't have the actual factory retrofit kit, but my towbar came with nearly all the electrics as per the retrofit EBA instructions. It didn't come with a flasher relay but I bought one of these from German fleabay. the one you want ends in 545 and has an extra pin (at pin 3 of the socket - the wiring should all be in place in a euro car). What does this pin do, you may ask? Well, if you look at your instrument cluster, just below the little bank of lights that contains your left/right indicator and high-beam annunciators, there is a single light. It is green and has little left and right arrows on it when illuminated.

I have fitted my relay even though I don't have the trailer module in yet just to see. The only difference at the moment is that when I turn on the hazard lights, this new annunciator lights up as well.

How this actually interfaces with the trailer or what the point of it is? Absolutly no idea :) Note that in the AHM wiring diagram, the left and right indicator signals don't even go through the AHM as indicators aren't monitored in the LKM so the only thing I can think of is that maybe that relay module is happier to drive two more indicator lights. I'm very curious what that extra annunciator does, though...
 

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Discussion Starter #12
The extra annunciator is a repeater of the trailer lights. When the trailer is plugged in, it gives visual indication that the trailer lights are flashing. These are the instructions from the installation manual:
 

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I'm very curious.
The only way I can see that working is some kind of load sensing inside the flasher relay - which may explain why the extra light goes off now when I put the hazards on.

i.e. with no trailer connected, the indicators draw enough current for 2 x 21W + 1x5W per side. If you connect the trailer, then suddenly when you turn on the indicators you are drawing an extra 21W for the trailer indicator so the flasher (being electronic) activates the extra light.

so when I put the hazards on, it's currently drawing 4x21W + 2x5W - well over the threshold and the extra light comes on.

accurate? who knows, but it's the best theory I have at the moment.
 

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I fitted an AUS LKM and it works perfectly.
A question if I may for Konfused Pete.
My M5 is also '90 UK spec with no 3rd brake light.
I'm just retrofitting this and the parcel shelf now from a donor 535i.
Did you also change the rear windscreen to suit or keep the UK spec screen?

Thanks
 

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I had to replace my rear screen anyway because it was pitted from some careless welding. The only screen I could get here was an au spec screen to suit a 3rd light. That's the only reason I got the light - to suit my new screen
 

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Righto then, thanks.
Mine has a fairly ordinary looking aftermarket unit which was a requirement for registration.
Even with the wrong screen, I think the factory one looks a lot better.

 

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So this 3rd brake light still isn't working.
The wiring was all there, and I've used the LKM from the 535i but still no go.

Some observations:
M5 is LKM-L and 535i is LKM-B, P/Nos are 61.35.1.379.371 and 61.35.1.379.372 respectively as per IvanDivas thread here:
http://www.m5board.com/vbulletin/e3...km-module-compatibility-across-e34-range.html

1990 wiring diagram (unsure if this is US only) shows the LKM uses Fuse 15.
The 535i has a Fuse 15 but the M5 has no fuse, or even any wiring to the fuse holder.


So 2 more questions for Konfused Pete:
1. What part no/type of LKM did you use?
2. Do you have a fuse 15?

Thanks in advance.
 

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I would think that if it was a bad fuse you wouldn't have anything working back there, or is that the case? I had that little wire go bad ( the one attached to the 3rd brake light ) and it drove me nuts trying to get the thing to work. Finally pulled that rear shelf and found the break , right at the fixture for the bulb. Also maybe that fuse 15 is a fuseable link? If you look at the inside diagram of the lkm you see the circuits for the brake lights are all connected, so you should have all three hot. If two sides are working then the third one should have power. Also as important of course is the ground (earth).
 

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Thanks.
Yes I need to do some more fault finding as you say, to rule out the obvious things, but everything else is working as it should.
It does seem however that the M5 is missing a whole circuit that is present in the 535i (Fuse 15).
It's not that Fuse 15 is bad or is a fusible link, it simply isn't there and nor are any connectors to plug a fuse into.
 

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I have no fuse#15 either - same as you, there's not even terminals behind it.

I never noticed that the '90 ETM says fuse 15. doesn't matter though, because the same fuse powers all brake lights so if one works, they all should. Refer to the fuse description under your fusebox lid.

My LKM is 61 35 1 390 350 labelled as "LKM-L AUS" which translates to the "highline" full featured one, AUS variant. I pulled that LKM out of a 750iL. Not sure what should be in our cars - best to find an owner of a genuine example and ask.

test if your wiring to the light is ok by pulling out the LKM. feed 12V to pin 15 of the LKM connector in the car and your 3rd light should shine.
 
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