Any suggestions please how to wire a brake light switch from the main harness

Easiest route is to run a wire from the live/poss side of your battery down to your brake light switch and another wire from the other terminal on your switch to the brake light bulb terminal. Ron

email (option): ronpier@talk21.com

Thanks Ron

i did have a little head scratch doing this , the wiring is positive earth ( wm20 ) and i may have made the mistake of taking the spur from the negative on the battery , it seem to work but only when running a complete new earth wire from the bulb ?

I also have a in line fuse on the earth / battery terminal , i spurred after the wiring on the brake light so this would also be would also be protected

Originally WM20's were negative earth but it works either way....And easy to change it back unless you have an electronic regulator fitted.

Ron

email (option): ronpier@talk21.com

Hi Ron

i have fitted the new harness to positive earth

Which is the best way to wire the brake light to poss earth . i have had no success so far

There are lots of variables here...Which pattern rear lamp holder are you using (originals had no brake facility)...are you using the WD headlamp switch with 'T' position ?

The rear lamp is a more modern road legal unit with 2 wires , on for the twin element bulb

The head light doe have the original switch

As mentioned i took the spur close to the negative wire on the battery , i thought this way the power would be constant when the brake is applied ?

I'd suspect that your rear lamp unit is not earthing via the bracket / mudguard, but through the headlamp feed. Does your tail light work on the 'T' position without headlight on ?

I agree with Ron (and I think with what you've done) that a separate live feed direct from the battery (via a fuse) is the neatest way to bring power to the switch and then on to the lamp, simply because the battery is so close.

yes the tail light works when on the " t" position

I have checked the brake light wiring , bulb and brake switch all fine when tested on a charger but on the bike nothing

This is how I did it. The black is the power coming from the headlamp switch to the tail light. The red comes from the brake switch and goes to the brighter 'brake' light in the bulb. I ran the wires up from the brake switch to a couple of inches behind the tail lamp. It's not necessary but I put in a plug so I could easily remove the lamp to work on without having to un-solder the wires. I plan to paint the wires Olive soon and tuck them away a bit more. It works perfectly.

Here's my post on how I modified the LED bulb to fit the housing.

http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1421853&cmd=show

email (option): moatjon [ at ] aol.com

Thanks

is the black on the switch a constant power source to the brake light ?

Yes, but only when closed and when the tail lamp is on. The brake will not light with the tail lamp off. If that's what you want, it's simple matter a matter of running the black switch wire back to the battery, easy enough. But I didn't want to run the risk of discharging the battery if for some reason the brake switch stayed closed or shorted. This way when I shut off the head lamp switch, the battery is isolated. And I intend to ride with the tail lamp on anyway.

email (option): moatjon [ at ] aol.com

My bike has no head light as such , it still has the original war time black out cover fitted so i would only use the bike in day light hours

Hence i only really need the horn and the brake light to work , i thought the easy option would be feeding from the battery but up to now no success

Lucas- Prince of Darkness! I don't intend to ride at night either but I live in the city with lots of motorcyclist clueless drivers, so I'm not adverse to having some extra visibility.

Rigging the tail lamp up to only work as a brake should be simple enough. If you can get the tail lamp to light, then to have it only work as a brake light is matter of diverting the wire to the brake switch. Just be sure the switch wires aren't in any way shorting to the frame.

email (option): moatjon [ at ] aol.com

battery ( non ground terminal ) to switch.
Switch to stop wire on globe socket
Check for ground on socket.
The ground path to the lamp housing is very poor and via the mounting bolts.
I solder a third wire on the spring which goes to a 3 pin plug that hides under top number plate bracket
So that plug has ground , stop & tail wires and is a blade plug so can not be cross wired & is easy to unplug when changing tyres.

email (option): bsansw1@tpg.com.au

Thanks Trevor

I will give this a go and let you know if the problem is solved

Thanks every one for the advise

The problem is now solved and the light works fine , i have had to run a spur from the positive side of the battery with a inline fuse .
Although the bike is positive earth and now has two fuses running from both terminals of the battery all this is hidden in the dummy battery box, looks good and tidy and works fine .

Happy new year to every one