I have an older GPS speedo (approx 3yrs) and I am just now testing the boat with the new unit. The gauge has the plug for external antenna and the 6 wire plug with wires for tattle tale, and Red Black White wires on the other side. The gauge comes on with the key and goes to Max, Half, zero like it is supposed to. When i was running the boat it wasnt registering anything. I know some of the new gauges dont use the white wire but it looks like i am missing something. Thanks.

white is normally for lighting in the guage. unless your talking about the single white wire that has a small plug on it. in which that goes to a nmea wire from anothe source say a g.p.s. good luck

try this

Thanks, it sounds like I need to relocate my antenna.