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Thread: 1976 R75/6 Head Light Bucket Wires?

  1. #1
    Registered User b25bsaboy's Avatar
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    1976 R75/6 Head Light Bucket Wires?

    Good evening,

    Of all the things that confuse the H#*l out of me is wiring, but not with the BMW that I am currently working on. Thanks to the technical stuff regarding wiring on this board it was easy.

    Now comes the kicker: After everything was put into place, checked and double checked I see that I have two wires left over. God I hate that! I have the old wiring board below and I cannot find the colour marking that is Green/Red that is supposed to go Spare 54. This is for the foot brake light switch. Also there is a black wire that after looking at the wiring diagram, beets me where it goes.

    P1020692.jpg
    The old board.

    P1020694.jpg
    Two wires that I am confused about, because I have no idea where they are to be attached to!
    Last edited by b25bsaboy; 01-15-2014 at 05:27 AM.
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 1976 BMW R75/6, 2009 R1200RT

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    Registered User lkchris's Avatar
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    Black wire is very likely something added by a previous owner.
    Kent Christensen
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    '12 R1200RT, '02 R1100S, '84 R80G/S

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    The Green/Red wire is the wire that goes from both (front and rear) switches to the brake light filament. The other side of both switches is a switched fused power source. I thought it was an "off the board" connection which the looks of your terminal supports. If what you are showing is the wire from the rear switch, where are the Green/Red wires from the front switch and the main harness?

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    In mine, the green and red is connected to the terminal marked "reserve" just below the hex nut under the bottom fuse. I cannot fine the green and yellow merged with black in any of my photos. If you don't have an answer soon, I'll go out and take the headlight off and have a look. I have a 1975 R76/6,

    Chip

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    Quote Originally Posted by cseltz View Post
    In mine, the green and red is connected to the terminal marked "reserve" just below the hex nut under the bottom fuse. I cannot fine the green and yellow merged with black in any of my photos. If you don't have an answer soon, I'll go out and take the headlight off and have a look. I have a 1975 R76/6,

    Chip
    I think there was a change in the wiring on the 1976. I have a 1976 R75/6 and will go check mine. I believe the terminal boards were different as well. As far as the OEM black wire, my memory says that it goes to the horn, but I will check that as well. Still curious where the other two G/R wires are on the OP's bike.

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    Here is an interesting update. I just checked the headlight bucket of my 1976 R75/6 and found that I have both wires unterminated as you do. There is a black with an insulated female terminal and a Green / Red with an insulated terminal. The Green / Red appears to come into the bucket from the main frame harness. Everything works (horn, front brake, rear brake). So maybe you are OK and the wires remain only a curiosity.

    I'll post pictures later today, but they both look as yours do.

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    Quote Originally Posted by beemerphile View Post
    Here is an interesting update. I just checked the headlight bucket of my 1976 R75/6 and found that I have both wires unterminated as you do. There is a black with an insulated female terminal and a Green / Red with an insulated terminal. The Green / Red appears to come into the bucket from the main frame harness. Everything works (horn, front brake, rear brake). So maybe you are OK and the wires remain only a curiosity.
    It would be interesting to find out where those wires go. Something to file away in the brain?

    Could you find out?
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

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    Quote Originally Posted by beemerphile View Post
    Here is an interesting update. I just checked the headlight bucket of my 1976 R75/6 and found that I have both wires unterminated as you do. There is a black with an insulated female terminal and a Green / Red with an insulated terminal. The Green / Red appears to come into the bucket from the main frame harness. Everything works (horn, front brake, rear brake). So maybe you are OK and the wires remain only a curiosity.

    I'll post pictures later today, but they both look as yours do.
    I have the same unterminated black wire also. Not sure about the red/green. I think I have some pics of the wires in the bucket. I'll look and post anything relevant. Cheers.

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    Registered User krpntr's Avatar
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    turn signal relay. according to my interpretation of Clymer.

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    Quote Originally Posted by Krpntr View Post
    turn signal relay. according to my interpretation of Clymer.
    Hmmm? I wonder if it is used to shut up that obnoxious turn signal beeper (that I removed) when the brakes are applied???

    Looks like this mysterious wire has been questioned before...

    http://www.bmwmoa.org/forum/showthre...at-s-this-wire

    It is looking now like it is there for the mechanical brake switch on the R60/6 which had a drum front brake. The R75 and R90 would not have needed it as the switch is on the under-tank master cylinder and is tapped from the main harness.
    Last edited by beemerphile; 01-15-2014 at 10:25 PM.

  11. #11
    Administrator 20774's Avatar
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    For the later /6 bikes and into the /7 bikes, there's no green/red wire in the headlight bucket. There are wires like this but they're all associated with two brake switches.

    But for the first year /6 bikes, there is such a green/red wire in the headlight attached to the 54 terminal and is associated with the brake switches. Also in the '74 /6 diagram, there's a black wire associated with the horn circuit.

    So, could it be a remnant from the earlier wiring harness? In the later /6s, they used different colored wires for this?
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
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    Registered User b25bsaboy's Avatar
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    Quote Originally Posted by 20774 View Post
    For the later /6 bikes and into the /7 bikes, there's no green/red wire in the headlight bucket. There are wires like this but they're all associated with two brake switches.

    But for the first year /6 bikes, there is such a green/red wire in the headlight attached to the 54 terminal and is associated with the brake switches. Also in the '74 /6 diagram, there's a black wire associated with the horn circuit.

    So, could it be a remnant from the earlier wiring harness? In the later /6s, they used different colored wires for this?
    Kurt,

    I think you are right in that perhaps my R75/6 was an earlier production in 1976 and the factory was still using up some older wiring harnesses. I know from experience that when vehicles and motorcycles are manufactured for the different model's manufacturers utilize one wiring harness that fits all. I know that this statement may have some people disagree, but from and engineering/manufacturing/supply chain model it only makes sense.

    Your comment about the green/red is for the earlier setup for the late drum brake set up and I suspect that the black wire is in fact for the horn. I haven't taken the multi-meter to do some further research and will do so later this afternoon.

    Thank you for your enlightenment as always!
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 1976 BMW R75/6, 2009 R1200RT

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