These are photos of the 1969 wiring diagrams from the factory service manual.
They will help, but you really should get one of the 68 Service Manual (the Pontiac manual, not Chilton's or Motor manuals). Reprints are available from any of the major Pontiac restoration suppliers or most literature suppliers.
thanks for the pics. I do have a pontiac manual, doesn't have what i need. My GTO is heavily optioned. P/W, P/Seats, Power top, A/C with a ambient air temp switch mounted on cowl for the A/C compressor. I am repairing the wiring harness for the fuse box and engine compartment. Question? On the fuse box there is a 12 gauge red wire that i marked "Battery FEED" One single wire with a red wire connector on it. Cannot find where it terminates. All of my other wires are connected. Any help or suggestions. Thanks again