Just thinking out loud. Have you tried turning on the light switch while it was off the bike? may be some kind of short between the switch and switch housing. When you on turning on the switch it may be grounding out to the bike.

Hi

I completey disasembled the switch, cleaned up the contacts, and still no joy :-(

so while you had the switch off the bike, did it still kill the motor when you turned it on?

Yep, as soon as I turned on the lights, the 20A fuse blew :-(

Okay, Does it blow the fuse when the motor is not running? If it does it may be grounding to the frame some where in the wire harness. With a multi meter you should be able to narrow it down.

Yep, blows the fuse without the engine running, and with the engine runing.

I would start checking the entire wire harness looking for breaks or burn spots. Check where the wire harness passes close to exhaust system and by the steering column. I've had clutch cable get smashed between the wheel stop on the steering and notice my wire harness was close to getting smashed.

sounds like yer at the stage where you have to strip the bike and
look for rub points on the harness... lift the harness away from the frame
at any lightly place it could have a short and try it.. steering head area
is a very good place to start or fuel tank or seat where it could have nipped
the harness while be put on...
hope it's not a internal short in the harness....

i assume the brake light & flashers work as normal ?




..

Hi Yeah, brake light, flashers, and passing light all work. Joe has offered to help me, next week sometime. Hopefully between us we'll sort it !!