The blue wire comes from the AC control, goes through the trinary switch, then to the compressor.

My understanding of one function of this switch is to turn on the fans only when the pressure exceeds a certain value.  This is controlled by the blue wire going to the fan relay (see the diagram).  The fan does not come on immediately when the AC is turned on.

(The trinary switch also turns off the compressor if the pressure is too high or low.)

ok, that helps. Friday I'm checking the wiring again, something isn't working right. Appreciate your help.

That sounds like a lot of work. But for the summer it is a very useful thing.