This page can point you to electrical wiring diagrams 2005 Honda VTX 1300 that applies for repairing lights on the VTX. this diagrams is so handy to learn so you can maintain or repair your own VTX lighting part.
*green color shows the ground
*orenge color is for left clutch side.
* blue color is for right(throttle) side.
*12 v for power source
You can find more the details stock wiring diagram of Honda VTX lightwires there.