There should be a small green power plug strapped to the wiring harness on the right side of the steering head. Meant for a Garmin GPS (for the Norge, but shared wiring harness ??).
Note:
- Thin wires, NOT for high power draw
- I had to put a 3A fuse in the unused position in my fusebox
- The plug is proprietary, but you can replace it with a USB outlet.
- Ignition controlled
- Hard to find, and not all Grisos seem to have it !
For higher power needs (trickle charging and wussy heated vest), I ran a fused wire pair straight from the battery. Guzzi are notorious for strange convoluted wiring, serving multiple uses, so I'd keep it simple. And update the wiring diagram in your manual !
The British auto industry invented bad wiring practices, but the Italians perfected them !