According to the wiring diagram supplied by Moroso, you need to buy at least an 8-gauge wire-length determined by car length-and run a small jumper wire from one of the main switch terminals to one of the small terminals on the switch. The other small terminal on the switch has another section of the 8-gauge wire connected to it and then up to the alternator. We found this didn't kill the power on our application. Instead, we ran one length of 8-gauge wire from a small terminal on the switch to the front of the car and hooked it into the switched wire that feeds the alternator. We then ran a second length of wire from the other small post on the switch back up to the alternator.