[Dave at Pelican Parts]

Console wires--
Brown is ground.
Red/white is switched power.
Green/black is the oil temperature signal.
Black is unswitched power.
Black/blue is power for the instrument lights.

Main harness wires--
Brown is ground.
Black/red is switched power.
Red/white is also switched power.
Black is unswitched power.
Gray is hot when the headlights (and possibly parking lights?) are on.
Green/black is the oil temp signal.

You plug the black/blue into the gray. The other colors just match up.

The green/black carries the signal for the oil temperature sender. If you plug both the one in the combo gauge and the one in the center console in, both will read wrong. (Though without numbers, it will be hard to tell.) I suggest only plugging in one. You can swap out the oil temp gauge in the console for a different gauge, but it will look a little different and you will probably have to run a wire for the sensor that feeds whatever gauge you pick.

--DD