Its a switch on the dash.
The pump will run if the switch is "ON"
AND
there is oil pressure OR the little overide button is pressed.

Do you need it? I don't know.

At this point I should probably declare that I still don't have an electric fuel pump. My car was in pieces a while back and I decided it was easier to add the wiring at that point for future use. I did however check to see if the wiring worked and it did and still does.