The little box is your "Automatic air recirculation control (AUC) sensor."

Don't blame me for that name, I'm just the messenger.

Look at your oil fill cap and draw an imaginary line straight fwd toward the radiator. There's a little notch in your shroud. That's where the sensor goes, and the line I see in your pic - colors as best I can make out, orientation, connector, etc, plugs into that little box shaped sensor. Assuming it's where it should be, but since you replaced the rad......