Customising bike, issue with new tail light...

[Water Warrior 2]

Originally Posted by awf1974

Attached is page 40 of parts manual, part 6 is "the spades that jut out underneath the brake housing," there is a plug on the wiring harness that attaches to these one wire of which runs all the way to the tail lights.

[attachment=0:2s3yq5u0]p.40.pdf[/attachment:2s3yq5u0]

That would be the front brake light switch and the wiring that connects to it.

[alantf]

Ah.....This is what threw me. What you're referring to is the actual switch, on the brake lever. When you said "brake housing" I thought you were referring to the brake drum. So......With the ignition on, there should be a voltage at the input side. Offhand, I don't know which spade connector that is, so you'll need to test each of the two cables to earth. If there's voltage at one of the cables, then that's the input side. Also, you can test the switch itself by removing both cables, then (with meter on ohms) put your probes on the two spades & get someone to squeeze the brake lever. If the switch is ok, the meter will show zero (or near as dammit) when the lever is squeezed, then go back to high resistance when it's released. Try this & let us know.

[awf1974]

Ok, after being busy at work I've got a couple of hours on sunday morning to get back to the bike...

Still have 11.5V at tail light, only milliVolts at switch input, with switch closed I have continuity and 0?, although when I take the probes of the switch spades the meter fluctuates, is this normal?

So I'll start tracing the continuity back to the battery, will let you know how it goes.

[alantf]

Originally Posted by awf1974

when I take the probes off the switch spades the meter fluctuates, is this normal?

Yes, it's just the meter electronics readjusting themselves.

It's starting to sound like a break in the wiring. Either a plug/socket problem or a broken wire (caused by rubbing somewhere in the circuit). There have been reports of rubbing near the chain, when the suspension moves up & down, so it might be worth a quick look there before you get down to checking every inch, back from the brake lever. Don't forget to do the "cable to ground" voltage check at every plug that you come across while tracing the wiring. Good luck!

[Water Warrior 2]

Seems like this is getting far too complicated. Assuming the tail/brake light was working properly to begin with I would just run a good ground to the new bulb holder base and go from there. Only 2 more wires to work with. A test light on the ends of the wires in the bike harness will determine what they are used for.

[alantf]

Now that he's found tail light +ve & ground, that only leaves one more to find - the brake light +ve -. Since the tail lght works, we can assume that the original ground is ok. The fact that he's getting millivolts from the other wire (which can only be the brake light +ve) suggests a broken wire or blown fuse. As he says that the other things associated with the fuse are working fine, that SEEMS to leave only the broken wire. It's possible that it's something to do with when he ripped the old fitting out.

[Water Warrior 2]

Okay, that clears it up a bit. I don't do well when electrical goes beyond a test light and a voltage meter. Alantf, what would we do without you?? Hmm, don't answer that.

[alantf]

:blush:

[alantf]

Well............seems like we never heard if he got the problem solved.

[beefjerky]

Old thread but I have just had the same issue!

Awesome buddy of mine figured it out:

Ground is White / Black, mount this to the bulb housing.
New Red connects to original Brown.
New Black connect to original Black / White.

Hope this might help someone else out!