The Norton Commando Ignition Switch is referred to as the Master Switch in the Workshop Manual.
Up until the MK3, it can be found above the left side footrest.
For the MK3 it was relocated to the Warning Light Console in front of the handlebars (the wiring is still the same though)
From 1972 onwards a four terminal, four position switch was used – Lucas Part Number LU30552.
The positions are:
- Parking with Lights (key removable)
- Off (key removable)
- Ignition Only (key captive)
- Ignition and Lights (key captive)
The numbers on the factory wiring diagram correspond to the numbers embossed on the bottom of the switch itself.
Here is an excerpt from the wiring diagram, showing the colour of the wires going in to the switch.
One point worthy of note – Bill Turnbill produced a colour coded wiring diagram (from where my first ones were reproduced from with his kind permission)
Bill’s diagram incorrectly labels terminals 3 and 4 (they are shown reversed on his diagram)
You will notice that the bottom of the Lucas LU30552 switch is numbered 1, 4, 2 and 3
So when you plug your cables in on the bike, be careful how this relates to the diagram (both mine as well as the ones in the factory workshop manual) which numbers 1, 4, 3 and 2.
- 1 NU (Brown and Blue)
- 4 UY (Blue and Yellow) – this is the single terminal
- 2 W (White)
- 3 NG (Brown and Green)
For one year only (1971) Norton and Lucas produced and fitted a three terminal, three position Master Switch to the Norton Commando.
The Lucas part number for this switch is LU39565.
Of course it is not available any more!
Norton sent out a service release in February 1973 introducing the new four position switch, which stayed in place through until the end of production of the MK3.
Hopefully this will help somebody!