I was going out for a ride and noticed my brake light was not working. After taking the lens off I noticed both filaments were lit so it wasn't that the brake light wasn't working, it was working too good. I traced it all the way up the chain and found both legs were hot all the way. A little further checking and I found that the problem was the brake light switch for the front brake.
The whole switch worked its way back into the hand control housing and the brake lever in the relaxed position was not making contact with the switch so the brake light was staying on. I cut a little custom nylon shim and wedged it in there and what do ya know, it worked.
The shop manual actually refers to a shim but says "if equipped" so I guess mine was not equipped. Should have been. Anyway, thought I'd pass it along in case anyone else runs into this.

 

Nice catch. Thanks for the new wrinkle on my brain...

 

The factory shim is a little brass v-shaped spring that can work its way out of position. Then when you open the switch housing it hits the floor never to be seen again.