These sensors have a 12" wire loom that exits the sensor with a 2 x3 water tight connector on the end. The terminals are labeled 'A' - 'F'. I consulting manuals and Dave Mumert's site (www.mumert.com/el2000.htm) to identify the terminals. Since terminal 'F' coincided to a blank on the wiring harness I did not check its purpose. Using a power source- 'A' to ground through a test light to limit load, 'C' & 'D' to positive, 'B' to a yellow test light to positive for detection of load, and 'E' to a red test light to positive for a detection of load. After a 20 sec. delay the ground circuit was completed to terminal 'E'.