I assume this is on an 05 GTO? There is a factory shift light there I think you are seeing. But for some reason the factory never programmed it, crazy to put it in and not program it even for the factory shift point. There is a guy that has hacked the instrument cluster computer that can activate it. He can even do custom things like add your name to the display. He is on the
www.LS1gto.com board often traveling around doing the installs.