[Richard]

Ok, I am going to try to help, but it is going to take some hands on work on your end.

I could take my thermostat off the wall and tell you what color goes to what, but that may not be the same wiring you have, so let’s go about this in a better way.

When you look at the wires on the Newell side, you will find one bundle of light gauge wiring sheathed in a common cable. It may have six to eight colored wires in it. You will find three wires coming to the tstat that are larger in diameter

RED/yellow stripe 12V positive
Light green. Ground
yellow/red stripe. Aqua hot

Brown. GL lo Fan
Green. GH. Hi fan
Yellow. C1 Compressor 1
Orange C2 Compressor 2

Some tstats use Blue for 12V pos, so connect the red/y to blue
Connect the tstat heat white to the Aquahot yellow/r

The tricky part to the new tstat is that the two GREY wires associated with freeze protection have to be connected together OR the compressors will not come on.

I am confused by your statement that a relay on the AC board that powers the tstat was replaced. I am not aware of a relay on the board that provides power to the tstat.

Waiting on your answer about the location of the relay in the picture.

By the way, did you get your transfer switch issue figured out?