Jason, This wire bypases the first resistor on the start up block and goes directly to the second resistor. This adds a little more current or power to the coil for start up. Then when the solenoid doesn't have any more voltage going to it to help start the car. It's not being used .Only during startup. You may work just fine w/o it. But there may be a time when you wish it was hooked up. If one end is already hooked up to the ignition coil resistor on the back fire wall, then the other end goes to the starter solenoid. John