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ferrarirobinson
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VBMWMO #9425
Joined: 03/08/2018
Posts: 11

I’m installing a 6v LED Taillight (from Benchmark Works). It’s a two function light that is as simple as it gets. Low Intensity for Taillight and High Intensity for The Stoplight Function. Bench test is perfect. From the terminal block behind the Battery the wires through the fender to the Taillight test fine with a 6v source connected the Lights work fine. Low intensity and high intensity.

Now the problem is:
With the bike wiring connected to the terminal block the Tail light function is on high intensity so that the Brake light will not work. (As the light is already on high intensity). The key is in the ”lights on position”. (turned right).
If you disconnect the tail light function, the brake light does work. With the key in the run only position, the brake light does work.

All of the above is without the engine running and a new 6v Battery.
I do have a Wiring Diagram.

History is, when the bike was made roadworthy a while ago, I must have checked for Brake light w/o the lights (taillight) and assumed it worked with the (incandescent) taillight also. Not sure now.
Also the previous owner did rewire the headlight and mentioned the 4 tangs that hold the ignition plate. The spare key, w/o the plastic housing, is the only one that works now. I absolutely do not want to take the ignition plate out and disturbing the tangs. Especially since l do not know how many times it has been done.
I did successfully disassemble and reassemble one in the early ‘70’s and the nub on my shoulders has been ground down and the fingers don’t do what they are told nowadays.

I’m stumped as to why the bike wiring seems to have the taillight on both functions.

Any suggestions will be more than greatly appreciated as “What I know about Electricity will
Shock you”.

Thanks
Charlie

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Charlie

Captonzap
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Posts: 68
Swap the two leads and see what happens

Swap the two leads and see what happens.

ferrarirobinson
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Joined: 03/08/2018
Posts: 11
I have tried swapping

I have tried swapping everything accessible (except in the headlight) many times). I have also bypassed the terminal block (behind battery) in case there was bleed over/by there. No change.

I seem to be aiming toward the hot brake power crossed with the taillight before the brake switch.
Maybe I’ll try bypassing the wiring harness by hooking to a light circuit in the headlight and bypassing the harness and going to the taillight. Hope that works, as I’m missing the best month of the year around here on this bike, or any bike for that matter. I’ve got others so won’t miss October, except the R60 might, which would be sad.

Charlie

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Charlie

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
Posts: 586
Led tailight

bench test ok
You have both high and low intensity

I suspect you may have the taillight and ground backwards
Make sure you have the led assy ground and bike ground connected properly
You need to verify what is really ground
In the diagram, and wired from the factory the center terminal on the terminal board behind the battery should be ground, but may not be if someone has redone the connections

Or the wiring on the terminal board is incorrect

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

bpw
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San Francisco bay
Joined: 09/21/2008
Posts: 20
I had a chafed wire inside my

I had a chafed wire inside my rear fender that was making all kinds of strange things happen with the tail light. It's a hassle running new wires inside the fender but not that bad if you pull the fender off and do it on the workbench.

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1963 r50/2 with 600cc conversion, 1971 Honda CL350, 1935 BSA 250cc, 2004 Ducati Multistrada, 2000 Aprilia RSV mille R, Kawasaki w650

miller6997
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VBMWMO #6997
Joined: 10/27/2006
Posts: 1101
Wires in the fender

I was able to replace the wires inside the rear fender without taking the fender off. I took the rear wheel off and removed the battery. Pulling from the tail light end, I got the old wires out without a lot of trouble. I then sprayed WD-40 inside the channel and fed a length of fairly stiff naked wire through the hole. I greased the new wires with vaseline and hooked them to the end of the pilot wire and was able to tug them through the tube.

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Jon Miller
'67 R69S
'13 F800GT
Altadena, California

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
Posts: 586
Wires in the fender

If you need to renew the wires in the rear fender you can use a smaller diameter wires as the new led tail/brake assy uses much less current than the older bulbs
You may also want to replace the licence plate bulb with a b15s (short) led bulb

Your ignition switch is not the problem although you may have the tailight and the brake light wire installed on the wrong terminals

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

ferrarirobinson
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Joined: 03/08/2018
Posts: 11
Tommy, I had already

Tommy,

I had already replaced the wires to the taillight and used 20 ga. I didn’t have enough of the original wire for me to tie onto. The new taillight test good from the Terminal block (behind the Battery).

Benchmarks LED Light has a 3 or 4 White LED License Plate Illuminator Function.

I have swapped wires daily and many times. It doesn’t seem to be the problem.

With the Key in the Lights Position there are bright lights on the tail light so no brake light illumination. This was the original problem.
With the Key in the Parking Light Position, there is a flicker when the brake is depressed, but not brighter.

I’m treading water here now.

So I think I can Temporarily bypass the bikes wiring and wire the light function directly on a switch and have a proper Brake Light till I might get this figured out.
I’m starting to get heckled by my riding buddies and a few non riders about time spent and no solution. Plus the clock is ticking on Fall riding. Winter is the time for Servicing (not necessarily solving Electrical problems though).

Will report Temporary fix success later

Charlie
.

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Charlie

ferrarirobinson
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VBMWMO #9425
Joined: 03/08/2018
Posts: 11
Thanks also tow1nca, miller

Thanks also tow1nca, miller 6997 and bpw for responding.

Bypassed the bike wiring behind the battery and direct wired and switched the tail light. For Safety.

Only because I’m missing the best month of riding in this part of the world.

This bike sure is FUN.(When it’s rolling)

Charlie

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Charlie

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
Posts: 586
Tail/brake light problem

Good for now
I think the wire from the brake light switch is connected to terminal #58 (power to tail light)and wire going to the tail light going to terminal #15/4 (power to horn/brake light)
Shouldn't be to hard to repair at a better time

Yea go riding
Just got back from 3 days in Vermont on my 55 r50 hack with Jet the Corgie
Wish I collected $1.00 for every picture that was taking of Dog in sidecar

Tommy

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  • Time to go home not happy face
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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

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