[Gunner]

I haven't looked at the wiring diagram for the details, but this is exactly how the IGN light in ERAs works. (Also in most vintage cars of my experience.) Does your EM use a different wiring harness from most Cobras?

EDIT: Unless I'm misreading the ERA wiring diagram, the IGN lamp is wired to the I terminal of the voltage regulator. Nothing else is connected there and the other side of the lamp appears to go to ground. Maybe it is that simple - I don't know offhand what the I terminal of the VR is for.