Vintage BMW Motorcycle Owners

Having trouble sorting out a wiring issue on my 1969 R69S. I have replaced the wiring harness which is pretty strait forward. At this point it seems everything works until I attach the tail light. There's a short and when I apply the brake pedal, the light goes out. With the tail light hanging by the wires it's fine. I'm suspecting the issue is in the head light shell wiring. There are many different wiring diagrams all seem a little different from what I've got. Anyone have a source for the late 1969 /2 diagram ? It seems there's power getting to the negative side of tail light. Thanks, Michael

I'm not aware of any 1969 specific wiring diagrams. Which diagrams do you have?

If you think there's power getting to the negative side of the light, hook the negative end of the meter up to the battery ground and use the positive lead on the meter to probe the wiring to see exactly where the 6v is and isn't.

Sounds like you have the ground wire connected to the brake light bulb or the connection on the 3 terminal connector behind the battery

To verify the ground wire
With key off connect you ohm meter to the frame or negative on the battery
remove the 2 bulbs and find out which of the 3 wires is ground and make sure it is connected to the ground side of the tailight socket

Tommy

Thanks for the tip. I am not very good with electric stuff. I can follow the wiring diagram no problem if the color code matches. I checked the tail light with ohm meter and have continuity and both the ground terminal and the black wire (power) #58 which runs from power side of tail light to #58 on terminal board in head light.
One more question, the left side switch(new) for high and low beam has different colors than the diagrams have. Not sure how to sort them out. The diagram shows yellow, yellow & black, black, green.
My new replacement switch, yellow ,yellow & white, white,green.
I appreciate your help and direction, I realize troubleshooting wiring on line is difficult. Thanks, Michael

I've looked at several different wiring diagrams and none of them have consistent colors, so I'm not sure what's correct. I notice in the newer Rinckes book, there's diagrams for lever switches and for swivel switches...I think the swivels are later. I would seem that in most cases, black would be ground and green would be power. But that's not what you have. So, I guess you'll just have to pick something and be as consistent as you can...plus document your work for the next owner.

Thanks for the tip. I am not very good with electric stuff. I can follow the wiring diagram no problem if the color code matches. I checked the tail light with ohm meter and have continuity and both the ground terminal and the black wire (power) #58 which runs from power side of tail light to #58 on terminal board in head light.
One more question, the left side switch(new) for high and low beam has different colors than the diagrams have. Not sure how to sort them out. The diagram shows yellow, yellow & black, black, green.
My new replacement switch, yellow ,yellow & white, white,green.
I appreciate your help and direction, I realize troubleshooting wiring on line is difficult. Thanks, Michael

Did this happen after you changed your wiring harness
or tried installing the new dimmer switch

switch
yellow same as yellow feed to low beam 56b connector at headlight receptacle
yellow/white same as yellow/black power for headlight 56 on switch board
white same as black feed to high beam 56a connector at headlight receptacle
green same as green

note:
Green Wire
original switch from 15/54 on switch board power to flash high beam 56a when switch is pushed in
later version switch from HO on switch board to sound horn when switch is pushed in

It ok to call me
leave message best time to call back if I dont pickup
413 628 3958

Tommy

Did you resolve your brake light issue and left dimmer switch

Tommy

Tommy, Thanks for asking. Not sure if it's sorted out yet. The left side switch I have correct. The situation with the tail light has me wondering. I'm just assembling the bike so some will not be known until later when the engine runs. I switched the positive and negative wires on the tail light and it seems to work. The tail light have a small tag that has 58 on it. That was the wire I traced to 58 on the terminal block in the head light. As far as I'm concerned the junction at the rear fender is wired correct. I'm not sure about the tail light it seems wrong to me. Michael