Right, but the first post didn't need the zener diode. Won't I essentially be making two wires one when I add the diode in line? Where will the power source come from at that point? I'd like to keep it all in the ignition's harness, but if I have to, I can run another wire from a constant for the led.Depends on exactly which switch you have as to the position of the connectors but pin 1 usually goes to the load, pin 2 goes to earth and pin 3 to the power source.
First post shows the wiring for an illuminated switch.