Honda-SOHC

SOHC.co.uk Forums => SOHC Singles & Twins => Topic started by: Craizeehair on January 21, 2026, 11:56:43 PM

Title: Headlight on / off switch wiring CB125K3
Post by: Craizeehair on January 21, 2026, 11:56:43 PM
I’m going through the wiring on the bike and seeing what’s chopped, needs repairing etc and so far I have been pleasantly surprised.

Could anyone advise on the headlight on / off switch wiring, I. Regards to the brown with blue tracer wire?

I can’t find a wiring diagram that shows this switch or a brown / blue wire. Can anyone helps as to where does this go and what does it do?

I’m probably missing something obvious but I can’t seem to find a wiring diagram that matches?
(https://uploads.tapatalk-cdn.com/20260121/2c2b2ea80637001a5f720e0c3b55a38c.jpg)
Title: Re: Headlight on / off switch wiring CB125K3
Post by: AshimotoK0 on January 22, 2026, 01:03:20 AM
Probably for a 'position' light for the European market it came from.
Title: Re: Headlight on / off switch wiring CB125K3
Post by: Craizeehair on January 22, 2026, 07:19:24 AM
Thank you, I presumed it was something I wouldn’t need but I can’t find a wiring diagram that includes this switch anywhere.
Title: Re: Headlight on / off switch wiring CB125K3
Post by: Bryanj on January 22, 2026, 07:39:27 AM
Those colours are frequently something to do with a headlamp fuse on the fours
Title: Re: Headlight on / off switch wiring CB125K3
Post by: BigAl (Alan) on January 22, 2026, 01:47:07 PM
The brown/blue wire is the supply from the head light shell switch (terminal Hi), it supplies the common terminal to the high/low beam handlebar switch
The UK spec bikes had the head light shell switch to accommodate the city light
Look up the CD175A 'sloper' wire diagram...very similar set-up.
Title: Re: Headlight on / off switch wiring CB125K3
Post by: Craizeehair on January 22, 2026, 01:50:24 PM
The brown/blue wire is the supply from the head light shell switch (terminal Hi), it supplies the common terminal to the high/low beam handlebar switch
The UK spec bikes had the head light shell switch to accommodate the city light
Look up the CD175A 'sloper' wire diagram...very similar set-up.
Thank you, much appreciated.
Title: Re: Headlight on / off switch wiring CB125K3
Post by: Craizeehair on January 23, 2026, 07:18:27 AM
Thanks for all the help, turns out it wasn’t a huge mystery after all. The brown / blue isn’t shown on any wiring diagrams I could find and I was trying to figure out what was what with the wiring on the controls that came with the bike, these as it turns out were not factory wiring. I have some NOS controls tucked away and when I checked those there is a brown / blue wire from those, so all sorted now, it is s a feed to the handlebar switch.