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Where does this wire go?
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Thread: Tail light circuit Reply to Thread
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  Topic Review (Newest First)
06-10-2019 05:24 PM
Smudge Frustratingly it's raining heavily...good ol' British summertime! Bikes stored outside so can't fix anything 😠 Cheers though Thorn, I will try everything you've suggested when possible.
I did expose the whole wiring loom a few weeks back to clean and learn about it all and see what was missing [attac2h]46005[/attach] . Everything according to the manual is there, but maybe not quite where it should be. At least now with your help I'm narrowing down what's fuc... Tomfooleried up. (I'd like to point out the issue of colourblindness at this point. Everything takes twice as long!!)

TonyO cheers buddy! Previously had the puck apart when this all started. Cleaned it up and covered in vaseline to protect it from moisture.
06-09-2019 10:23 PM
Thorn Sounds like you're so far in the weeds that the schematics in the manual aren't going to be of much use.
For curiosity's sake, when you compare your 8-wire plug at the junction box with the schematics, what wires are attached at pins 7 and pin 17? From your ignition/tail light behavior, it sounds like the PO moved all the dash/tail light circuitry on the red/blue wire from pin 7 to 17 to isolate that circuit from the headlight.

The ignition puck is most likely fine, since the circuit still passes through the puck without a vampiric draw when the tail light fuse is removed.

I'd unplug the tail light and the 8-wire JB connector, then check the ohms between the tail light wire (red/blue now on pin 17???) and ground, and as a sanity check also measure the the tail light constant voltage leg to ground. You'll likely find there's a path for current, and that will at least limit what wires to look at. Follow the speedometer light wire backwards as far as you can (he had to have chopped the harness somewhere) and check the splice. Same for the tail light. I'm guessing he kept the factory tail light connector on the bike and spliced the new hardware in further to the rear?
06-09-2019 03:05 PM
TonyO I would check the ignition switch "puck". Based on symptoms and your location i would suspect water in the puck has caused corrosion, open it up and look for the damp green mess of verdigris caused by corroding copper. That's usually what I found caused most electrical problems when I lived in blighty, Same goes for the JB, the circuit card is not coated so will corrode readily and the connectors are unplated copper so will do the same. Clean all the crap out and a shot of WD-40 to dry it up should fix it
06-09-2019 05:28 AM
Smudge Ha! Tomfoolery is a polite way of putting it Thorn!! Pulling the tail light fuse doesnt kill the headlight, that has its own fuse. Brake light still works as well as that is on a separate circuit.
Haven't quite managed to get the 'park' to work. You have to jiggle the key all over the place to engage the steering lock whilst wiggling the handlebars...will test your theory in a bit to see if park helps.
06-08-2019 10:26 PM
Thorn Yeah, the cut blue wires would be for the running lights in the front turn signals.

Which actual fuse did you pull? The "tail light" fuse in a stock bike is not hooked up to anything, but since there's been some tomfoolery with the wiring, things might be completely different. If things are still SORT of stock, I would guess that you pulled the headlight fuse to get the tail lights and speedometer to go dark (also killing the headlight)?

If you put the ignition in 'park' instead of 'on', does the drain go away? 'park' isolates the tail light circuit from the front lamps (dash and headlight).

Most likely culprit for the current draw would be a faulty headlight relay in the junction box. If 'park' eliminates the draw, try doing the "blue wire mod".
06-08-2019 09:07 PM
Smudge Running lamps? Would that be when the turn signals are on constantly and blink off when you turn? If so...I'm in England. Mines an American import so the constant lights were disconnected due to some law. (English folk get confused apparently by a constant orange light.) There's two blue cables cut off doing absolutely nothing...according to the manual they would be the constant feed?

Brake and tail have their own bulbs, and the license plate is lit from a clear lense underneath the bulbs (classy) The previous owner had the decency to still have the original brake/tail light in a box which I hooked up to check.

Yes having read nearly every thread the junction box pops up quite a lot! Hopefully that's worse case scenario! I'm thinking maybe the constant running lamp cables need attention and tracking down the license plate cable?
06-08-2019 08:15 PM
Spockster Those lights I mentioned should be in the same circuit as the tail light. So I was thinking to start removing bulbs until the draw goes away.

Not the actual turn signals, but the running lamps combined with the turn signals up front. The rear signals don't have running lamps, in stock form.

The license plate is lit by a clear lens in the tail light, or has it's own bulb?

Connecting the original light still produces a drain
Which original light?

If it's not the light itself, must be the wiring leading to it. And of course there's always that crazy junction box.
06-08-2019 07:24 PM
Smudge No dash lights, they're all missing. The pin connectors are clean and wrapped in the back of the headlight. Turn signals are good... Headlights good. I have an aftermarket brake/tail light that has the license plate light included. Connecting the original light still produces a drain so it's a case of knowing what else is on the same circuit as the tail light...I can't make it out from the wiring diagram. With the fuse in there's a draw between the battery and the live cable of 0.64v. Taking the fuse out drops this to 0.10v.
06-08-2019 04:50 PM
Spockster Running lights on the front turn signals, dash lights, license plate light?
06-08-2019 04:43 PM
Originally Posted by TonyO View Post
Does the tail light still work correctly?
It does indeed. As far as I can tell all cables and connections from the the light are as they should be
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