IKBA.co.uk Messages

IKBA Messages | Contact IKBA | Bikes on RealClassic.co.uk | Classic Bike Stuff on Amazon.co.uk
Back to the Message Board

Click here to search eBay using an item number or text description...

how hard can it be?

Posted by Expat Stu <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Expat+Stu' width='330' height='300' border=0 style='border:none;'> on April 19, 2026, 3:53 pm

Right, I have rigged a slave battery to try and get the brake light switch to work.

The bulb lights all the time until I press the pedal and then the light goes out.

All I have is (+) to the switch then (-) to the bulb, which is earthed.

It is a cable with the switch built in.

I am not an electrician, what am I doing wrong?

How can I reverse this action?

Re: how hard can it be?

Posted by Andy C <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Andy+C' width='330' height='300' border=0 style='border:none;'> on April 19, 2026, 4:29 pm, in reply to "how hard can it be?"

Just thinking out loud, what happens if you pull the cable from the other end - could it be that you have the cable the wrong way around?

Just a thought.

Who needs a signature anyway......

Re: how hard can it be?

Posted by Expat Stu <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Expat+Stu' width='330' height='300' border=0 style='border:none;'> on April 19, 2026, 5:52 pm, in reply to "Re: how hard can it be?"

Ah! Clear thinking Andy C but it only fits one way - with the adjuster for the rear drum lever

<a href="https://ibb.co/8gN0S6xj"><img src="https://i.ibb.co/b5QP8zvr/cable.jpg" border=0></a>

This cable has now been shortened...

Re: how hard can it be?

Posted by 6TDen <iframe src='https://members5.boardhost.com/classicbikemart/info/user=6TDen' width='330' height='300' border=0 style='border:none;'> on April 19, 2026, 6:22 pm, in reply to "Re: how hard can it be?"

As Andy says, it all points to the switch being back to front. Try turning it around an see what happens.
Den?

Re: how hard can it be?

Posted by Will <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Will' width='330' height='300' border=0 style='border:none;'> on April 19, 2026, 6:43 pm, in reply to "Re: how hard can it be?"

This might sound completely daft but as a fully qualified Grade A1 auto electrical numpy I have to ask....
If the switch can only be fitted one way round can you reverse the wring at the bulb holder?

Re: how hard can it be?

Am I missing something but I can’t see the switch in the picture unless it’s that funny looking cam thing on the rear wheel.
Den

Re: how hard can it be?

Posted by the old one <iframe src='https://members5.boardhost.com/classicbikemart/info/user=the+old+one' width='330' height='300' border=0 style='border:none;'> on April 19, 2026, 7:46 pm, in reply to "Re: how hard can it be?"

ok , as per what andy stated , ay present , you are pulling the cable at the brake petel end , and this is turning the switch "off"

try disconnecting at bothe the lever and the rear brake , then try PULLING at the wheel end , see if the switch works then

Re: how hard can it be?

Wonder of the switch has been incorrectly fitted to the cable ?

You say you shortened it - did you take the switch off the cable when you shortened it?

Who needs a signature anyway......

Re: how hard can it be?

Posted by Expat Stu <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Expat+Stu' width='330' height='300' border=0 style='border:none;'> on April 20, 2026, 7:08 am, in reply to "Re: how hard can it be?"

It was custom made by venhills, so the problem is more likely to be my wiring. I will take a photo of the switch later

Re: how hard can it be?

Posted by geoff the bonnie <iframe src='https://members5.boardhost.com/classicbikemart/info/user=geoff+the+bonnie' width='330' height='300' border=0 style='border:none;'> on April 20, 2026, 7:58 am, in reply to "Re: how hard can it be?"

Looks like Venhill has made you a normally closed switch that operates to open when you operate it.

Re: how hard can it be?

Posted by the old one <iframe src='https://members5.boardhost.com/classicbikemart/info/user=the+old+one' width='330' height='300' border=0 style='border:none;'> on April 20, 2026, 8:50 am, in reply to "Re: how hard can it be?"

or he has gone past the "switch" point settings , and it is in "on position at rest" , hemce suggesting he pulls inner cable at other end , to put switch contacts in rest / off position

Re: how hard can it be?

Posted by Andy C <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Andy+C' width='330' height='300' border=0 style='border:none;'> on April 20, 2026, 12:56 pm, in reply to "Re: how hard can it be?"

Could be that Venhill cocked up - might be worth contacting them. As Geoff says the switch appears to be normally closed instead of open.

Who needs a signature anyway......

Re: how hard can it be?

Posted by the old one <iframe src='https://members5.boardhost.com/classicbikemart/info/user=the+old+one' width='330' height='300' border=0 style='border:none;'> on April 20, 2026, 1:08 pm, in reply to "Re: how hard can it be?"

as I said earlier , its possible that the position of the cable is holding the switch on , then when pressed , the cable is passing the switch contacts and turning off
as posted before , remove cable at both ends and pull at brake drum end till off (bulb), then pull at lever end to see if it goes on

I would be very suprised if venhill had fitted a normaly on switch , its more likely that the cable has been reversed or set in wrong place

a question

Posted by the old one <iframe src='https://members5.boardhost.com/classicbikemart/info/user=the+old+one' width='330' height='300' border=0 style='border:none;'> on April 20, 2026, 1:28 pm, in reply to "Re: how hard can it be?"

when you wired the light up , which way did you do it
did you run an earth wire to the buld , then a liver wire to the switch , and live from the swith to the bulb

OR did you run a live wire to the bulb , and a earth to and from the switch

either would in effect work , but may cause some problens with switching if you were switching earth off and on

and a second question , is this a double filliment bulb , or do you have any other bulbs in that light fitting ,

are any of the bulbs LED

Re: how hard can it be?

Fair comments old one.

I wonder how the switch senses that it has to switch from off to on and vice verca?

Who needs a signature anyway......

Re: how hard can it be?

Posted by Expat Stu <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Expat+Stu' width='330' height='300' border=0 style='border:none;'> on April 22, 2026, 8:37 am, in reply to "Re: how hard can it be?"

sorry for the delay, life etc...in situ

remove duplicate email lines

then I found the old cable and pulled the switch apart:

so it looks to me that the switch is permantly "on" until the cable moves and breaks the circuit - but how does that cause the bulb to light? there are 2 festoon bulbs, one rear light and a seperate one for the brake. I ran a (+) to the switch, then from the other side to the bulb and the bulb holder is earthed.

Re: how hard can it be?

Posted by Expat Stu <iframe src='https://members5.boardhost.com/classicbikemart/info/user=Expat+Stu' width='330' height='300' border=0 style='border:none;'> on April 22, 2026, 9:09 am, in reply to "Re: how hard can it be?"

not LEDs

Re: how hard can it be?

Posted by the old one <iframe src='https://members5.boardhost.com/classicbikemart/info/user=the+old+one' width='330' height='300' border=0 style='border:none;'> on April 22, 2026, 9:18 am, in reply to "Re: how hard can it be?"

« Back to index

[ IKBA.co.uk Messages ]

IKBA Messages | Contact IKBA | Bikes on RealClassic.co.uk | Classic Bike Stuff on Amazon.co.uk

Thank you for your support...