BSA Owners' Club Forum

The BSA Workshop => Singles => Topic started by: phill on 13 December, 2017, 15:23:23

Title: C15 ignition switch
Post by: phill on 13 December, 2017, 15:23:23
Hi, can anyone help with this one?
I bought a new loom and it has sockets for the lighting and ignition that go into pins on the back of the switches. My switches are not like that - the wires connect directly to the switches. The light switch seemed to marry up quite well but the old ign switch has 6 wires connected to it with connections as follows
12 brown/white ammeter
13 purple to rectifier
14 white neg side of coil
15 black/white pos side of coil
16 green/yellow alternator
18 brown/white number 5 pin on light switch

The new loom has only 5 connections to the socket
12A brown/W to rectifier and ammeter
13 W to coil -
15 black/W to coil +
17 G/Y to alternator
18 black to pin 5 light switch

Confusing matters further is the fact that I have fitted a rectifier/regulator

Can my old ign switch be made to work with this lot. If anyone has done this and can post a wiring diagram I would be most grateful

Cheers,
Phil



 
Title: Re: C15 ignition switch
Post by: MICKREEVES on 16 December, 2017, 08:47:07
I have had similar problems on my C15 and B44.
I do it the hard way.
Draw a circuit with all the logical connections, and put in the wire colours.
Many of my wires are different colours each end!
Mick
Title: Re: C15 ignition switch
Post by: AWJDThumper on 17 December, 2017, 13:54:47
Hi Phil.

Your harness is from a late C15/B40 as shown. Hope this diagram helps.

Title: Re: C15 ignition switch
Post by: Calvin on 17 December, 2017, 14:12:44
I had the same problem with a new harness I bought from Newark auto jumble. I ended up buying a proper Lucas harness and fitted it in no time with no problems.
Title: Re: C15 ignition switch
Post by: AWJDThumper on 17 December, 2017, 14:18:20
As far as I can see, the harness in question is slightly different from the earlier ones but is functionally more or less the same. I am actually restoring a 1967 C15 at the moment and will probably make up the wiring harness according to the above diagram depending on what switch connectors I've got available.