Chuckster· Premium Member
2005 GSX-R600 Anniversary Edition
Doubtful. The brake light system is LEDs. It shouldn't backfeed like that.Now I understand.
I think you have a bad ground connection (high resistance) at the B/W wire. The other lamps are trying to seek ground through the brake light when it is not operating.
To test, just put a jumper wire between the B/W and a good ground and see if you loose the potential that you are seeing on the W/B brake wire. If you do, you need to track down the ground problem or add another ground.
I'm guessing that you are using an LED type test light. I don't think you would get this indication if you used an old incandescent bulb tester. (it take more potential to light up).