The weird thing about the Lowrane is it's power cable. It has 3 bundles of wires for it. 1 is the display unit power cable. 2 is for NMEA 2000 power cable. 3 is data cable.
Here's picture from the manual on the parts I'm confused about. Maybe it's just the terminology that is confusing me.


In the diagram, it shows the outside bundle is the display power set. But IRL, it's the middle on the harness.
If i'm reading it correct, I'm suppose to power the NMEA wires, if I want the GPS to work. Or maybe I'm reading it wrong. I dont really understand the whole NMEA deal, but it seems they are trying to standardized a network with other vendors to mix and match stuff.
Anyways, I tested the unit today with just the display unit power cables and I get a lock on the GPS unit. From what I can tell, it seems to be working just fine. But I wasnt moving. Since it was able to lock onto my position, I assume it should track around no problem.... Granted, it is slow to lock into your position. I'm guessing roughly 1 min.
I didnt bother to install a power switch on the display cable. There is a warning though.
"The NMEA 2000 network bus is always on and constantly drawing power. You must connect NMEA power to a switched power source so you can turn off the network when not in use. Failure to connect to and use a power switch will drain your boat battery, which could stop your boat's operation."
But assuming I dont have to power the NMEA cable, I should be fine without a switch, correct?