I'd have to agree with the previous posters who suggest a new harness. You can pick up one on E Bay for a few hundred dollars or less if you are lucky. Get one with lots of circuits, tear out what remains of the old harness, and start fresh. You get a complete kit with instructions and tech help line if you get stuck. Wires are correctly color coded / labelled, and guages are correct. In my case, I used a Painless Universal truck harness which is GM color coded, and had ample ciruits for what I needed, plus a few extra if I decide to install an electric fuel pump or windows down the road.
