Brake light not working

[Dom]

Since I've had my xs650b the rear light hasn't worked at all. I've replaced the bulb and performed a continuity test on the blue wire where it enters the headlamp, the yellow has continuity to the rear brake switch and front brake switch but I've not traced it any further as I can't work out where it goes. The earth/ground seems fine, any ideas?

 

[5twins]

Are you saying you have no tail light AND brake light? The tail light doesn't light at all? You're dealing with two different circuits here. The tail light is powered by the headlight on-off switch. Turning it on sends power on the blue wire to the tail light. The brake light switches are a different circuit. Both are fed power in on a brown wire coming from the key switch. When the brake light switch is activated, it connects that brown to the yellow and power is sent down it to the brake light.

 

[Dom]

Yeah nothing runs at all

 

[Dom]

Could my odd gauges and dash with no brake lining lamp when my bike has the sensor on the rear drum part of the reason?

 

[Jan_P]

Not so easy to have an informed opinion non stock wiring
I would measure voltage bottom up
Starting at the rear light ...there is some connectors there around the fender I believe and work upstream .
My view is that it is in 95 98 % of the cases a connector switch lampholder or so rather than the wire itself.
When you find the Voltage somewhere upstream .. then service the items described above downstream could be a plan

 

[5twins]

That rear brake sensor switch is on a totally different circuit, not related to or connected to the tail and brake light circuits in any way, other than being fed power from the same source as the brake light (brown wire from key switch). I don't think there's any way for it to make the tail and brake lights not work.

For the tail light, I'd take a look at the on-off switch in the right handlebar control. Maybe it's blue wire has broken off, or the R/Y that feeds the power in. For the brake light, I'd check to see if the brown wires feeding the brake light switches have power.

 

[Dom]

I'll take a look 5twins, thanks for the suggestions. I didn't think the brake lining switch could be an issue but didn't want to rule it out.

Still can't work out the dash weirdness though!

 

[Dom]

Sorted, I'm not sure how the earth is meant to be on a 650b but mine had two, one at the back of the light that as far as I can make out is insulated by two rubber mounts but coming from that is a second wire that on my bike had been soldered to the bulb reflector but had broken off.

Reattached it and now I have light!