i have found a hole bunch of disconnected wires, cut wires, and what not. I have found where most them go, but no to sure about this one in the ( in the pic) i found it located in the radio/ stick area, it has a orange and black wire going to it,

88 Gta 305 Auto

 

That LOOKS like a factory radio plug. The radios used to have 2-3 plugs. Im assuming it has an aftermarket radio in it now? Either that one wasnt needed or someone cut the necessary wires and "hard wired" the radio right in.

 

Also sometimes there are "dead" connectors within a car. Your model could have had something deleted however the plug is still there for the vehicles that have said deleted component. Unless you are chasing after something just let er be.