Here is another diagram. This is nothing new, but can really extend the life of your switch. Instead of all the current going thru the switch contacts, just a small ammount to trigger the relay passes thru the switch. I did not show the other 2 wires at the starter, the batt cable and one going to the ign coil. The one you want to pull is on the outside of the starter sol( away from the block). On my car this has a 90 degree connector. I did not cut this connector just use a insulated female spade connector on your added wire and plug it into the orig wire. That way if you ever have trouble, and suspect your relay, just unplug here and plug orig wire back into the sol where it was. If you used the ign coil relay wiring I posted you can use the power and grounds for both relays. I have mounted several relays next to the coil, very neat. I always use relays that have a built in mounting tab, easy.