WELL!!! This thread crawled back out of the "old"!! Colors change, I don't know what wire you mean. If you mean the one from the ballast to the coil, NO!!! That is not 12V, it goes THROUGH the ballast from 12 and is therefore less, AND hooking to the coil will further drop both coil and choke voltage.
Turn key to run. Probe ballast. Terminal with highest reading is what you want. I would fuse the lead to the coil, because nothing else in that circuit is.
