WIRING PROBLEM

Hi Everyone
I have nearly finished restoring my 1975 candy sapphire st70 but I have a wiring problem so cannot take it for mot, the brake light works fine when the lights are on but will not work when the lights are off, It has a new battery fitted and I have checked all the wires are connected correctly, any help with this would be much appreciated.
Thanks Graham

That's a weird one, have you tried to change the bulb?
It could have fused internally, worth a try?

Let us know how you get on

Your brake light wiring is simple and straightforward and should be easy to resolve.
6v battery power is taken from the red multi connector under the seat , circuit is made at the switch and continues directly to the bulb. An earth connection (back to the neg. of batt.) is required for the bulb of course.

Thanks for the replies I have put in a new bulb and the brake light works fine from both the handlebar lever and foot brake with the lights on but not with the lights off, has me really confused !

Try running a separate earth wire direct to the bulb to check your earth connection, that could be the problem.

Just had another look at it, took the lense off the back light and with the lights on the brake light works fine on tickover, with the lights off the brake light will work but only if you rev the engine very high, doesn't seem to make sense at all

Thanks Chief tried the earth wire onto the bulb and that was the problem bad earth, I thought it couldn't be the earth as it worked with the lights on.
Thanks again Graham

Good - Sorted.
When your lights were on I guess it found a way of earthing thru that circuit.