Headlights wont work!!

I have a strange problem with my Z500B headlights.

They were working perfectly for the Mot 2/3 weeks ago. They now don’t work. The pilot light works. The fuse for the headlight hasn’t blown. Indicators work, tail lamp, number plate lamp, brake lights all work, but no headlight.

The bulb hasn’t blown as i have tried the wire from the pilot light on each of the terminals for the headlight and the bulb glows nicely.

The only thing I have done with the bike since the MOT, other than ride it, is jump start my girlfriends Suzuki off it. Could this have damaged something somehow?

I have started getting to the switches/wiring/fuses but don’t really know much about electrics, I have a multi-meter, but don’t know how to use it either (i only bought it the other day)!!

Could check power into and out of dimmer switch. Maybe spray some WD40 inside the swutch while clicking it back and forth.

Good Luck!

both the wires had corroded and come off the resistor between the headlight switch and the dimmer switch, might just be 29yrs of crude corroded through the wires or it could be the excess of power from the jump start.
anyway the battery is now dead so i'm charging it up again, hopefully it'll hold a charge and i haven't fucked the battery.