Commando headlight problem

Hello Folks, I'm new to this forum but not to Nortons. I just picked up a '75 Commando in great shape...BUT I have a headlight gremlin that is making me nuts. It worked when I first got the bike. I can flash the HL okay, all other lights work, pilot on, etc. But the hi/low beams quit. I have no juice to the bulb. Bulb is good. All fuses are good. Seems like no connection between the rt hand control and the dimmer switch. Is this an ignition switch problem?

Any help/ideas appreciated.

Alex
1975 MK III Commando
1968 Commando

Does your ignition switch have a fourth position which gives power to the headlamp switch?

Take the right handlebar switch apart. Locate the blue wire in the switch. If there is 12 volts at this wire when the ignition switch is turned to the "ignition and headlight" position, the problem is in the right handlebar switch. Check the contacts. If there is no voltage check at the connector under the tank or at the ignition switch.

Ron L said:

If there is no voltage check at the connector under the tank or at the ignition switch.

Click to expand...

As it's a Mk.III, the wiring from both handlebar switch clusters feed into the headlamp shell where they both connect to the headlamp harness section-so the headlamp connections should be inside the headlamp shell, not under the tank.

Edit: One of the three Mk.III multi-pin plugs beneath the tank (where the headlamp harness connects to the main section) does have a blue wire, but this is a Canadian model assimilator wire.

As it's a Mk.III, the wiring from both handlebar switch clusters feed into the headlamp shell where they both connect to the headlamp harness section-so the headlamp connections should be inside the headlamp shell, not under the tank.

Click to expand...

Thanks for the correction. The connections were in the headlight on my MkIII, but the harness was such a mess I thought the previous owner had put them there.