2008 precedent headlight wiring question.
 

I have an early 2008 precedent that was a 4 x 12v set up.

Cart had the factory harness and pigtails. Headlight and tail lights Install went fine
Came with a fuse with wire and hook ups on wires. I took power as instructed from battery 4 (+) and the negative blue single wire in the factory harness near controller...

Just swapped to 6 x 8volt setup, and when pressing throttle the lights dim to zero. I hooked everything back as it was except (+) is hooked to battery 6 (+)

I have a 48v to 12v reducer pulling off the entire pack to a fuse block. If I pull the (+) from the fuse block and leave the negative in the factory harness (-) will this fix the issue? If not id love recommendation on how to fix the power issue.

Thanks!