Both absolutely perfect for the job
I'd be inclined to completely rewire from the solenoid back to your new switch and then to a source of 12v via a 30A fuse and isolate the old wiring to the solenoid...NewcastleFalcon wrote: ↑29 Nov 2022, 16:18
For all it seems like a Starter button should be the simplest of installations to do, the white signal wire disappears from the key switch immediately into a bundle of heavy harness trunking which disappears up towards the offside of the car. I thought it would work its way left towards the passenger side in a fairly obvious fashion and be nicely break into able centre stage.
I used to do similar when installing 'helper' relays into XMs and Xanitas when their ignition switches became tired.
As for a running engine inhibit, you'd need to find a signal source that will operate a relay to isolate the supply to the button both when the ignition is off and when the engine is running. Maybe the easiest one is to pick up the earthy end of the oil pressure warning light sender for the first condition and an ignition switched supply for the second...