Headlight Wiring Troubleshooting

[RazeOrion]

While I'm waiting for my NOS carb to come in, I decided I'd tackle my lighting system wiring. I tested the headlamps individually and they test fine, so I don't have an issue there.

However, it seems my wiring from the healight bowl and the control switch on my handlebars is reading at 0 ohms meaning they need to be replaced.

Does anyone have any information on the kind of wiring I'd need to rewire them myself? I don't feel like spending extra money where my know-how can save some.

I attached a photo with the correct wires marked out.

 

[CaptChrome]

I think they are 18 gage multi-strand wire. It is odd that all three wires would be bad at the same time.

 

[size030]

thanks for the info

 

[avemachina]

Before you rewire these, it might be worth checking if your headlight switch is the true culprit. There are a couple of things that could be happening--the wires that connect to the posts within the switch could be damaged, or the slider could be corroded or bent in a way that doesn't complete the circuit properly.

When you open that switch (don't forget the phillips-head on the side of the thumbswitch) all it is, is a copper strip that slides to close either the black to green (hi-beam) circuit, or the black to yellow (lo-beam) circuit. I'd pay special attention to the black wire (it might be yellow/black, not just black)--it's always connected, so the whole thing poops out if that wire goes bad.

I had to remove the corrosion from my own switch, since copper is pretty good at developing patina. Just regular old Brasso and a q-tip was enough.

If you really do find that the switch is OK, it's 18GA stranded wire terminated with bullet connectors (you can find these at home improvement stores or auto parts places). You can just replace the wires directly that way.

 

[avemachina]

I wanted to add, if you do end up needing to redo the bike-side wiring, my 400S has two yellow wires (I think the headlight and tach are wired together) and I've never seen that 2-into-1 connector for sale, so here's how to make a jumper and work around that using single bullet connectors.