Hey Don, here are some pictures of the gauges and the wiring that we talked about on the phone.
This is the front of the gauge
Back side of same gauge
Middle plug of same gauge
Back of 2nd gauge that is not digital and show trim, water psi, and mph
And lastly, here is a picture of a gauge under my dash that says smartcraft on the face, but that is it. The back has part #110135-A Pass. Best I could tell it has 3 inlet/outlets on the back side but only 1 is being used and it seems to go straight to the back of the 2nd gauge above. On the back of the 2nd gauge, the 2nd plug goes/comes from the gauge shown at the top with the 3 plugs. The other 2 plugs including the larger middle one that is pictured run to the side of the boat and seem to go to the motor. I didn't see any blue wires are blue plugs that you mentioned.