[BombardierBomb]

Did the handlebar switch get shorted out from the rain? It shouldn't have, as you've said, but that would be the first thing I'd look at.

Unless the contactor itself somehow failed, but it's usually tucked away safe from rain.

 

[BombardierBomb]

To the right of the radiator, if you're seated on the bike. That's been where I've seen 'em anyway. Mounted on that downtube of the frame