Hello great sirs. I made a rookie mistake and didn't take a picture before replacing a part so I forgot which hose goes where. Can anyone tell me how I can tell which is the hi hose and which is the ref hose. If it even matters? I don't understand the logic behind the two hose.

Are they correcr or crossed?

This is the sensor i replaced

 

As I recall, they are different sizes. You should be able to tell from that.

 

Look at the metal line sizes off the EGR tube and match them up with the EGR Sensor size for size.