Beware, it involves a total of 7 relays, as 2 of the wires from ignition need to turn off when starter is pressed

Could I not put in another switch to power the rest?Gayno wrote:There are 2 problems though.
1st: The panel you have is designed for the switch to kill power just to the starter circuit, not the entire vehicle electrics as you're planning.
2nd: 2 of the circuits actually disconnect when you engage the starter, so you need to use relays to accomplish this also.
Here is the ignition switch from the Prelude wiring diagram:
As you can see, the WHT-BLK and YEL wires don't have any contact from the 3rd (starter) pin.