Tom...

I could be misunderstanding the question. What I'm hearing is that you want to be able to tell the pcm to switch between normal and optional shift modes using a control button. You have a diagram for a circuit that is used by the OEM to command a change in shift tables, but you have not installed the components to make the circuit work.

Are you using a PCM and calibration that are already set up for a 4L80E? If so, you only need to duplicate the factory wiring through the "tow/haul" switch. Activating the switch tells the pcm that you want to change shift mode. The PCM doesn't know the difference between "sport" or "tow/haul." It does what it's programmed to do in alternate shift tables. If you do not tow or haul then you can change those table to provide performance shifts.