2004 Lightning ground locations as follows: A few running production changes result in subtle differences but basics below. Also click link...see thread I initiated as user_deleted 10 years ago. You have either a failed in-series connection or component. Charging system DC output to battery still exists with 1 or more failed/missing ground connections.
1-Negative batt cable to left frame rail plus BLK-2
2-BLK-1&3 to right frame rail
3-ECM grounds to main harness access(see SM schematic)
4-Braided "dog-bone" wire at main horizontal frame connector support
5-Engine-to-frame main vertical frame connector support
6-VR should be grounded to frame mount. Mostly overlooked but highly recommended
7-See link below---main wiring harness to frame grounds vicinity of steering neck
CHECK 30A BATTERY MAIN FUSE. If blown, cause is always either faulty VR or positive short-to-ground.
https://www.buellxb.com/forum/showth...y-and-Solution