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TR6 Brown wires multiplying

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matttnz

matttnz

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Anyone know what these are for? Under the drivers dash of my TR6 (1974 UK CR) are a bunch of small brown wires that are taped off and as far as I can tell are not live. I can't seem to find them on the wiring diagrams and everything seems mostly in it's place (the car's for the most part pretty original). Assuming there's not other big brown wires getting funky and making small baby brown wires...what are they for?

Brown Wires.jpg
 
Standard European color code calls for brown ground, but no guess as to what they ground. Of course, grounds can be made at any point on the body. Tom
 
In europe, N is ground.
I think that would be confusing.
 
I have not seen brown used for ground on European DC equipment. Brown is +V, Blue = 0V, and Black = signal (at least for 3-wire sensors for example). My method for remembering this is that blue=cold and that the ground is cold.

Regardless, in Lucas wiring brown is un-fused and permanently "hot" (not switched). Are you sure that these wires are not "hot"?

At least one wire in your picture has a "blue" crimp on terminal. Perhaps that indicates that these are wires added by the previous owner, that they do not follow the Lucas color code, and that they were for a component that has been removed.
 
The wire coding in the rest of the car (radiator fan and fuel pump aside) is stock and black is ground. I've gone over some of them with a multimeter and get no voltage across to a grounding point. One of them disappears into the steering column, the rest into a loom under the dash heading back toward the centre (but my hands are too big to follow that much further...).

I suppose the PO may have had them planned for some extra devices (12V socket?) but I have no idea why so many as the old (but not original) radio was already wired (off the fused live purple light circuit as far as I can tell)
 
dklawson said:
I have not seen brown used for ground on European DC equipment. Brown is +V, Blue = 0V, and Black = signal (at least for 3-wire sensors for example). My method for remembering this is that blue=cold and that the ground is cold.

Regardless, in Lucas wiring brown is un-fused and permanently "hot" (not switched). Are you sure that these wires are not "hot"?

At least one wire in your picture has a "blue" crimp on terminal. Perhaps that indicates that these are wires added by the previous owner, that they do not follow the Lucas color code, and that they were for a component that has been removed.
Click to expand...

You are absolutely right. I jumped to a false conclusion from a recent BMW issue where brown is ground. Black is pretty much universal ground in Britain. Tom
 
I bet they go to the iggy switch and thre PO was trying to look somewhat correct
Good thinking Douglas
 
I just had a look at the '74 schematic.... it looks like the "N" (brown) should be +12v (unfused as Doug states) and feed the headlight switch and the starter relay. The fact that you do not show voltage when measuring across ground leads me to think the PO added the wires.
By the way, I have a .pdf of the '74 schematic; if you need it, just let me know and I'll be happy to email it to you.
 
Thanks Elliot. I have the auto-wire diagram, and the one in the workshop manual. Is that the one one you meant? There's less stuff on the UK models and unless they put in a US loom I'm not sure what they might be.

If it's different, you could always drop it over when you're in town ;)
 
Tape them over with black tape and forget about it. You'll eventually have bigger things to worry about than a couple of mystery wires.
 
I wonder if there is continuity from one to another? When I first got my TR3A I had some unknown wires that turned out to be the opposite ends of wires to nowhere.

Yeah, for the Germans a brown wire is a ground.
 
I guess it's a good thing I don't currently own any German cars. I'm old enough now that I would certainly get my color codes mixed up between British and German cars.

Having Googled for the brown wire color code after reading this thread I found that Toyota also appears to use brown for ground wires.
 
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