I thought the button was a TEST button, to check if the system is charging. I don't think there was any point in a dipping headlamp with a black out mask. In fact I'm fairly sure that dip switches were deleted around the time of the four position WD light switch. Ron

email (option): ronpier@talk21.com

I think this is a subject I need to read up on! Ron

email (option): ronpier@talk21.com

Hey Ron,

Maybe I wasn't very clear in my question, so there is the '4 position light switch (test-off-T-H) under the saddle. And there is the push button on the headlight panel. (And im looking for the puch button.)

There is more info on the switch here Ron:
https://www.wdnorton.nl/Electrical_system.htm

Some extra info cause I have already studied the light switch itself, and the nice thing is that the test function (turn left) is self-returning. So you have to hold the button to the left to enable the test function. This connects the D of the dynamo in the switch directly to the rear light, so it must light up when the dynamo is working!
The other 3 positions are the same as the normal military light switch.
(just see you standing next to the bike, holding the switch, revving the engine and looking at the tail light :D)

Greetings Ben

email (option): benbakkers@live.be

Hi Ben. I was aware of this late war economy system and the description on Rob's site clears it up in my head. I thought you meant the push button as a headlamp dip switch. But of course it switches from pilot bulb to headlamp bulb. This would then save the cost of an ammeter and about two meters of cable.

Obviously to do the test, you must first back up to a wardrobe mirror. :smile:
At some point they even deleted the press button Ron

email (option): ronpier@talk21.com

I seem to remember discussing a theory about the completely blank panel, it allowed a replacement standard headlamp to be fitted to an early machine with the switch panel in the tank.

Rob

email (option): robmiller11(a)yahoo.co.uk

Hi Ben,

I have the complete panel including the push button for sale. Send me PM and I will send you some photos of it.

I also have several of the late war under the saddle switch for sale, if someone is looking for that 1. All in great condition.

Regards,
Bastiaan

email (option): wdmotorcycles@gmail.com

@Ben: replied to your message.

email (option): wdmotorcycles@gmail.com

Hi Bastiaan,

Do you have the bracket for it?

And if not a rough drawing ?

Hi Henri,

Lex Schmidt has one for sale

Sven

Thank you Sven

Hi Bastiaan

I would also be interested in one of the switches if you have a spare

Cheers Barry

email (option): deadhorsesdontgetbackup@hotmail.co.uk

is it possible some one could post a picture of the back of the U39-L15 switch?

thanks, barry

The same, or an extremely similar switch that does the same job, is fitted to the headlamp of a 1967 BSA B44 .....Ian

email (option): ian@wright52.plus.com

it seems that the test (test-off-T-H) switch under the seat i have is working the same way as a 4 position (off-T L H) switch would that is fitted in the headlamp, im thinking mine has the wrong switch cam fitted, im trying to find a picture of one to se what it should look like,

barry