OK, I am struggling to resolve my lack of rear tail light and brake light.    I need all of the big brains on this forum to help me out again!

- I checked the ground connection at the light first and it is good.

- I checked the bulb

- I put power to the unit under the seat (picture #2 under the black sleeve) and it powers up the light when I do it direct, so it has to be something in front of that connection.

- I checked the ignition switch connections and all wires are sodered as they should be.

What should I look at next?

Is there a way I can trouble shoot the connection under the tank (picture #3)?

It would help me if you described exactly what you mean by "put power to the unit under the seat"..  Plus you've taken a picture with the wires pretty much hidden under the cover.

First question is if other battery powered lights (neutral, turn signals) and horn work ok?

There are two medium blue wires coming out of the key on US models.  One to the headlight (AC) and one to the taillight (DC).  And If I remember correctly the one to taillight is actually a Blue/White wire that goes from key switch directly to the taillight.  With a simple test light, you should be able to to see if there is battery power at the blue/white to the taillight with key in "lights on" position .  (It could be the solid blue goes to tail and blue/white goes to headlight.  Either way, one of the two should have battery power with key in lights on position.)

Brake light is a completely separate circuit.  Brown wire powers the rear brake switch.  Brown should be powered with key on.  With brake pressed and key on, you should have power to the other wire (yellow?) at the rear brake switch.   Again, follow that yellow to taillight and should have power to brake light.  Front brake switch is similar with brown power but green/yellow out of the switch to the brake light (green/yellow splices into brake yellow somewhere in the harness)

So you have 3 ways to power a light filament in the taillight.  If ground is good and bulb is good it seems unlikely all 3 circuits went bad?  So that's why my first question is if other battery powered accessories work...  could be a blown fuse or a bad key switch or something. 





 

MarkT.... Thank you for the response.

What I mean by putting power to it under the seat was that I took a small 12v battery and put direct power to the black ground wire (ground) and both the blue and yellow wires individually, and both  the brake and running light came on.

The pic here shows the wires that I put direct power to.

 

The next thing that I did was to check the Brown wire connection located under the fuel tank with the brake pressed and key on.......   I do not have power there....... So you suggested checking the fuse,  I am only aware of one 10A fuse on the bike which is under the seat area.    Is there another fuse related to this that I need to check?

 

No, only one fuse. If brown is not hot with key on, you won't have neutral light, turn signals, brake light, or horn.

Also note that brown should have power all the time with key on...  not just with brake pressed. 

I looked at the main switch legend in your pic and I probably have it backwards... looks like solid blue connects to red (and brown) with key in "lights on" position II so solid blue (L=blue) is likely taillight wire powered by battery.

They show LW (blue/white) connecting to yellow with lights on so blue/white would power headlight.

If the legend is correct.

The neutral and turn signals are not working either......

The headlight and gauge "back" lighting are working.

System was originally 6v - have you converted to 12v? If not, 12v battery might have blown the bulbs.

And the key is in the second 'on' position when you're testing?