1994 Chevy C1500 Truck Brake Light Mystery

What all does the "Convenience Center" contain? Does the Cigarette lighter work? The convenience center should have more than one wire. Orange is probably constant 12 volts.

Black ground?  Whatever colour GM uses for illumination, possibly an ignition or ACC. That's a nice name for a ciggie lighter and an ashtray. Antonia, are you a female person or did you use the name to get a faster responce?  It worked! Make sure the orange has 12volts perm, feed a ground to one of the other pins, I'll bet the third pin should be coming from the door contacts.