Ignition Advice Needed

DaveinCanada · Friday at 1:14 PM

Hi,

I'm have '75 commando. When I turn the key to the "Ignition Only" position (first position clockwise), I get the following:
1. My rear red lights come on. But when I step on the rear brake pedal, they go off.
2. No headlight comes on but the small red indicator light on the headlight casing comes on. Moving the toggle switch does nothing.
3. When I push the top button on the left handle bar control, my headlight comes on and goes off as I push it.

No other ignition position turns on lights. I've tried all switches and buttons in different positions. I'm trying to understand what lights are supposed to come on at each ignition position. Does the bike have to be running for lights to come on (i.e headlight only comes on when bike is running). Any advice would be appreciated.

L.A.B. · Friday at 1:37 PM

If it's a Canadian model then the rear light pilot light and instrument lights should come on at Ignition. The headlamp should also come on when the engine starts. All lights should work at the ignition and lights position. See the information in your MK3 manual for the Canadian models.

DaveinCanada said:
Moving the toggle switch does nothing.

That is likely bypassed for Canadian models as it should not be possible to turn the headlamp off with the engine running.

DaveinCanada said:
3. When I push the top button on the left handle bar control, my headlight comes on and goes off as I push it.

It should switch between main (Hi) and dip (Low) beams so something seems wrong with the switch, bulb or headlamp bulb circuits.

DaveinCanada · Friday at 1:51 PM

L.A.B. said:
If it's a Canadian model then the rear light pilot light and instrument lights should come on at Ignition. The headlamp should also come on when the engine starts. All lights should work at the ignition and lights position. See the information in your MK3 manual for the Canadian models.

That is likely bypassed for Canadian models.

It should switch between main (Hi) and dip (Low) beams so something seems wrong with the switch, bulb or headlamp bulb circuits.

@L.A.B. The upper button on the left control only turns the headlight on when pressed. When it's not pressed, no headlight. Oh, and I don't have any ignition lights. Just a key in the middle of the handlebars. Do I need to turn that middle key as well?

L.A.B. · Friday at 1:58 PM

DaveinCanada said:
. The upper button on the left control only turns the headlight on when pressed

The upper 'button' should slide forwards and backwards and selects either Hi or Lo bulb circuit it isn't used to switch the headlamp off or on so I don't understand that.

DaveinCanada said:
Oh, and I don't have any ignition lights. Just a key in the middle of the handlebars. Do I need to turn that middle key as well?

Middle key? The only other key apart from the ignition key is the steering lock key which doesn't do anything electrical.

DaveinCanada · Friday at 2:20 PM

L.A.B. said:
The upper 'button' should slide forwards and backwards and selects either Hi or Lo bulb circuits it isn't used to switch the headlamp off or on so I don't understand that.

Middle key? The only other key apart from the ignition key is the steering lock key which doesn't do anything electrical.

The button I have is a push button only. It doesn't slide. I will try to take a pic of my bars.
I checked out the middle key and you're right, it doesn't do anything.

DaveinCanada · Friday at 2:28 PM

DaveinCanada said:
The button I have is a push button only. It doesn't slide. I will try to take a pic of my bars.
I checked out the middle key and you're right, it doesn't do anything.

Here are some pics of my handle bars and controls

L.A.B. · Friday at 2:35 PM

They're not '75 switch clusters (below). They are from an earlier model or it's not a '75 electric start model. The twist grip and master cylinder also aren't '75 type.

L.A.B. · Friday at 2:44 PM

The button you are pressing would be the headlamp flasher of the earlier model. An earlier model would not be Canadian.

DaveinCanada · Friday at 2:47 PM

L.A.B. said:
They're not '75 switch clusters (below). They are from an earlier model or it's not a '75 electric start model. The twist grip and master cylinder also aren't '75 type.

Apologies, it's a 1973. Just checked the identification plate.

DaveinCanada · Friday at 2:49 PM

DaveinCanada said:
Apologies, it's a 1973. Just checked the identification plate.

Knowing that and seeing your diagram, the direction indicators don't work when in the ignition position.

L.A.B. · Friday at 2:56 PM

DaveinCanada said:
Knowing that and seeing your diagram, the direction indicators don't work when in the ignition position.

Well, they should so the flasher relay, switch or wiring needs looking at.

L.A.B. · Friday at 3:01 PM

As it isn't '75 model then you need to use this manual for wiring diagram, etc.

http://www.classicbike.biz/Norton/Repair/70up_Commando/70upCommando.pdf

L.A.B. · Friday at 3:56 PM

The ignition switch on the pre-Mk3 models should be on the left hand side of the airbox, the only thing up front should be the lighting switch in the headlamp shell.

http://www.classicbike.biz/Norton/Brochures/1970/1973NortonLineUp.pdf

DaveinCanada · Friday at 4:36 PM

DaveinCanada said:
Knowing that and seeing your diagram, the direction indicators don't work when in the ignition position.

Good to know. Thanks

DaveinCanada · Friday at 4:37 PM

L.A.B. said:
Well, they should so the flasher relay, switch or wiring needs looking at.

They direction indicators should work in the ignition position? I'll have to look at the wiring

DaveinCanada · Friday at 4:38 PM

L.A.B. said:
The ignition switch on the pre-Mk3 models should be on the left hand side of the airbox, the only thing up front should be the lighting switch in the headlamp shell.

http://www.classicbike.biz/Norton/Brochures/1970/1973NortonLineUp.pdf

Yes, mine is on the left side of the airbox.

L.A.B. · Friday at 5:38 PM

So the lights should work when the ignition key is turned to the 'ignition and lights' position with the headlamp switch at the (pilot, tail and instruments) position and the headlamp as well at the other switch position as only the headlamp feed passes through the switch (blue/yellow to blue) as power for the other lights comes from the ignition switch (terminal 3, brown/green wires).

Andover Norton - LIGHTING SWITCH 2 POSITION 34660 LU31780 (LUCAS) - 06.8024

LIGHTING SWITCH 2 POSITION 34660 LU31780 (LUCAS)

andover-norton.co.uk

WZ507 · 2025-03-11T19:12:05-0600

DaveinCanada said:
Yes, mine is on the left side of the airbox.

There are many electrical connections underneath the gas tank. If you are troubleshooting electrical issues, removing the gas tank to provide full access to this area would be a reasonable place to start.

cjandme · 2025-03-11T20:49:05-0600

"3. When I push the top button on the left handlebar control, my headlight comes on and goes off as I push it."

Could it be that the Hi-beam is burned out, inside of the headlamp.

Ignition Advice Needed

DaveinCanada

L.A.B.

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DaveinCanada

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DaveinCanada

DaveinCanada

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DaveinCanada

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DaveinCanada

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Andover Norton - LIGHTING SWITCH 2 POSITION 34660 LU31780 (LUCAS) - 06.8024

WZ507

cjandme

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