[ray_mcavoy]

If you follow the wires after they branch out of the taped up bundle, they should lead to the plug on the neutral safety switch. The neutral safety switch is located inside the cab on the steering column just before it passes through the firewall.

The yellow wire runs from the "start" terminal on the ignition switch to the neutral safety switch. Then the purple wire runs from the neutral safety switch, to the bulkhead connector (in behind the fuse box). The bulkhead connector is where the majority of the wiring passes through the firewall. From there, the purple wire continues on to the starter solenoid.

The neutral safety switch is closed when the transmission is in "park" or "neutral" and should be open in all other gears, preventing the engine from being started while the trans is in gear. By temporarily unplugging the yellow & purple wires from the neutral safety switch, it will open the circuit (preventing the engine from starting) and verify that you have correctly identified the wires without having to cut one of them.