2000 Yukon Ipod hook up to tape deck please help

Ok i want to add a plug in thru the wires that go from the tape deck to the sterio unit does any one know what color the input wires are that go from the tape deck up to the sterio or head unit i thought i could just splice on to them and ad a miny jack on the side of the center console instead of that goofy tape with the wire that has the miny jack