Today, I figured out what the problem was. This morning, the system appeared to be adjusting the temperature to something I had originally programmed the first time (before I realized the wiring was wrong, and therefore had to start the installation program a second time.) So, even though my phone was no longer connected to the thermostat, the thermostat seemed to have some prior instructions still embedded into it. Looking on the face plate of the thermostat, I was able to find a setting that allows the user to "delete the previous program", or something close to that phrasing. Once I did that, then tried the Google Nest set-up program again on my phone, the thermostat was able to connect to my phone. But, who would have known it was necessary to do that? The disappointing thing here is that none of the instructions or articles I've read about "why won't my thermostat connect to my phone" mention this specific problem. Another way this could have worked out is if I had been able to re-do the wiring diagram, while keeping the transmitter connected to the phone. It seems the only way to provide a new wiring diagram to the phone is to un-install the device, and start the setup process all over again.
