Backfire = electrical
 

I am have some prolbems with the carb on my 84 GSL.
I recently put one on that has most of the rats nest removed. Odd thing happen I turn the lights on while I had the directional (blinkers) on at the sametime. This causes a backfire that sounded like a shotgun blast. Could it be the black with white stripe ground wire that runs to the carb is bad?