Are you sure you have one on your boat?
What devices do you have on your existing NMEA2000 network? Have you checked the "Device List" in settings on your Lowrance unit to see what's connected, and if the unit "sees" the network?
If you have a "Point1" antenna, or other networked device, you can trace the cable to find the backbone.
Need more input here in order to help.
Edited by DFW-fisherman (07/18/17 05:06 PM)