All of the MSD units I have installed needed 12 volts in run and start posistion on the smaller red wire. I had to also tap the red wire into the ign 2 terminal off the ign switch or it wont get spark until you let the key back to the run posistion. Basically it needs to see the ign 1 & ign 2 to it so it has power in the crank and run mode. Ron