ok, so just checking over the bike today for its mot and noticed that when i apply the front break it doesn't illuminate the brake lights. the rear brake switch forks fine.

so i plugged the 2 female connectors into another master cylinder housing and it didn't work. down to connector block and disconnected and cleaned the connections (red plastic one yea??) and its made no difference.

Ideas??

Short those female connectors together and see what happens. If you get brake light, it is the switch. If not, time to start chasing wiring.

Already tried that steve, looks like its a panels off job

That sucks. Good luck. Let us know how it goes.

Start by seeing if it is getting +12v into the switch (black/brown) then test if the output wire reaches the brake bulb filament. You can do that much without removing panels, it might prove fruitful.

Ok, so electrics aren't my strong point.
Multimeter is broke. But shorted one of the switch connections on the frame and it popped the fuse. I guess that's the 12+v??
So I got a test wire and connected it to the Green and yellow on the rear brake connection. And got lights :)

So what does that mean??

Brake light switch?

geoff33 wrote:Brake light switch?

dont think so, by touching the 2 connectors together that should have put the lights on if that was the case?

hannakournikova wrote:Ok, so electrics aren't my strong point.
Multimeter is broke. But shorted one of the switch connections on the frame and it popped the fuse. I guess that's the 12+v??
So I got a test wire and connected it to the Green and yellow on the rear brake connection. And got lights :)

So what does that mean??

My guess is it means you don't have continuity from brake switch out to brake bulb. If I were guessing I would say it's where that wire is crimped inside the loom to the same wire for the rear brakelight switch. But frankly without a multimeter there is zero point in guessing.

Check 12v into switch. Check 12v through switch. Check 12v follows to brake light. This will tell you where the fault is. Or you can keep guessing. Guessing games are fun, right?

If you grounded one of the wires going to the front brake switch and it blew a fuse, then you have proved that 12 volts reaches the switch. As suggested in a earlier post, at the front brake switch, if you connect both wires together and the stop lamps lights then the wiring is ok and the switch is faulty, otherwise you have a wiring fault leading from the switch back to the stop lights.