I could have sworn it was orange... maybe I've got my wires mixed up...
it is an extra wire on the ignition switch.
Its been a while since I've been in there, but if i can remember it right, there are two wires you need to actually start the car, and two you need for it to run. there is an extra wire that is on the "start" circuit. I thought it was orange. but I could be totally wrong about the colors.
From what I remember, if you look at the back of the ignition, it should be pretty obvious what wires are part of what key positions. But I could be getting other cars mixed up

don't ask why I've seen the back of enough ignition switches to get them confused.
even when I explain it, it still doesn't sound good. lol.