B40 wiring diagram

[Greenfield]

I don't find the Haynes wiring diagram of much use for my 1961 B40. I'm particularly interested in the connections to the ignition switch. Can anyone point me in the right direction?

[berniej]

Would highly recommend the Rupert Ratio book which includes alternative options like 12V conversions.

Cheers,
Bernie

[AdrianS]

I have got a copy of the wiring diagram in the owners handbook. I think it is no better than what you have got.
It is difficult to fathom out how the switch wiring works - if anyone has a simple guide, I wouldn't mind having a copy too!

[JulianS]

This is from the Lucas service manual. Not an easy loom, you need to trace the alternator output Green/Yellow cable via the ignition and lighting switch in  the different switch positions, until it gets back to the rectifier.

With the riginal 6 volt system, with no voltage regulator in circuit, the lighting switch is also a charging switch to crudely control the alternator output.

With ignition "on" the green/yellow a/c output enters ignition switch at terminal 17 and leaves at terminal 18 as black and goes to lighting switch terminal 5. With headlight "on" it emerges from terminal 7 as green/black to the rectifier giving full alternator output.

Following the wiring in different switch positions will show how the output is reduced by the internal connections.

A 6 volt system with a proper regulator and a 12 volt system dont need the coil switching to control output.

[Greenfield]

Got it.
I should be able to now see the wood from the trees. Its always a bit of an issue when things have been messed about over the years, and wires no longer have the correct colours.
Many thanks, I knew that there'd be an answer out there somewhere.