My 77 Piaggio Bravo has a dim rear running light at Idle and blows the bulb within the first couple of rides. The wire for the running light is a gray color and has continuity with ground. I traced the short through the harness to the headset where both sides of the headlight bulb connector is also shorting to ground. What the Hell? Why is that? I need a good diagram! I don't know what side of the connector is supposed to be ground if any on the headlight. Can anyone help me? Chris from Raleigh NC.