Unidentified wire to ignition.
 

Hi folks, I'm in need of a little guidance, again, dealing with wires going to ignition switch. According to wiring diagram I should have a dark green going to ground, which I do not have. Everything else matches up except for a brown wire that is going to the acc along with a brown and white striped wire. The brown and white are on the diagram, however, the solid brown one is not. My question...where does the solid brown wire go? Kinda at a loss here, so any guidance would be greatly appreciated. Thank you in advance for your time.
Dave
BTW it is a 66 gmc 1500. Figure that might be useful information lol.