Headlight switch also turns on brake light

[gspd]

Glad my72r60's problem is resolved.
My point was that almost all electrical problems on these relics can easily be trouble-shooted (trouble-shot?) with a simple test light.
No need for DVMs, scanners, and laptops, as are necessary to diagnose illnesses on most vehicles manufactured in the new millenium.

Now that everything works satisfactorily, my72r60 can start dvm-ing all his individual circuits to death and try to get them up to exact battery voltage. Good luck with that. Or he can just ride it another decade or two until something else stops working and get the test light out again. Tightening up connectors and terminals, and maybe replacing a few old wires and corroded fuses, etc. is always good preventive maintenance.

btw,
IN THEORY... Installing an extra relay and its associated wiring is 'electrically' the most accurate way to get an exact 'battery volts' reading.
IN REAL LIFE... Calibrating the voltmeter via its adjuster screw to indicate exact voltage at the battery is more convenient and cheaper, and has no detrimental side effects.. If it's good enough for Porsche, it's good enough for me. (not to mention the K.I.S.S principle.)
If battery voltage varies from the norm, your voltmeter will instantly warn you either way.

ps - Learned a new word! All this time I thought 'Anathema' was Euretha Franklin's grunge rock band : )

[Airbear]

^^^ A fine traditional hijack leading to a very useful discussion. Thanks lads. And well done My72R60 for solving your issue.

The wiring in my old 'relic' (1974 R90) has been hacked and re-hacked (mostly by me) over the years. I've just sent 48 quid off to Vehicle Wiring Products in Derbyshire for a supply of cable in all the right colours, enough to rewire a couple of bikes. I've also found the 'flag' terminals with soft covers, very similar to the BMW ones, on eBay.

By the way, I no longer use the terminal board in the headlight bucket and have shifted a bunch of stuff to the cavity under the tank that was previously home to the master cylinder. In this Century of the Fruitbat a bike needs many more power, switched power and earth terminals to drive relays, charging ports and other accessories. Extra fuses are also useful and that means more terminals. I have found these gadgets very handy - they can be ganged together on a strip of brass to create busses:

[Rob Frankham]

Glad my72r60's problem is resolved.
My point was that almost all electrical problems on these relics can easily be trouble-shooted (trouble-shot?) with a simple test light.
No need for DVMs, scanners, and laptops, as are necessary to diagnose illnesses on most vehicles manufactured in the new millenium.

That's one way to look at it of course but to me that's like using cow dung moss and cobwebs to treat a flesh wound when you could use antiseptic and sticking plaster.

ps - Learned a new word! All this time I thought 'Anathema' was Euretha Franklin's grunge rock band : )

Well now you know where the name comes from ...

Rob