I did some checking and the LGC 4000’s aren’t failing. Almost all the time water gets in one of the tee’s or connections. This will interrupt the power and the antenna will give you the message “module not responding”.
If this is not the problem then it could be a power issue with the power node, check the ground and hot wires or a low voltage issue that will make the 4000 give a “module not responding” message.
For the water issue, after the system dries out, unplug the antenna and plug it back in. This will reset the antenna and it should work. The other thing to do is to take your antenna and plug it into a buddies’ boat who has an LGC 3000 or LGC 4000 antenna (these networks have red or black tees and the 4000 will plug right in, a blue network needs an adapter cable for the LGC 4000 to connect) and see if it works on that boat. If it works then there is a problem in the boat. Usually though the unplugging of the antenna and plugging it back in will fix the problem.
If you have water getting into the NMEA backbone somewhere and you are experiencing this problem, get some dieletric grease/compound and put grease into all the connections. This will keep water out.