My comment towards the original units were that I had (2) Carbon 12 originally. One at the bow and one mounted in the dash. I ordered the new Carbon 12 and put it at the console along with the original Carbon 12 that was mounted in the console. I put these two units on a Bass Boat Technologies dual mount. The new unit is mounted on the left and the original unit is on the right. The unit that was at the bow is still there. If I turn the new unit off then that leaves the two original units running and they work flawlessly. I’ve changed the Ethernet cable running to the new unit twice and it doesn’t correct the problem. That’s the first thing we did when the problem started. After that we ran 10ga stranded wire through the boat and that didn’t fix the problem. So I’m thinking it’s either a voltage issue or the new graph is bad. I’m running a 31 Interstate AGM that’s not even a year old. That should be plenty of power to run these graphs.

There are two other configurations to test. Swap the Carbon from the bow to the bad location at the console. Note whether the problem moves to the bow with the Carbon unit. The final config just closes the loop on all possibilities - borrow a Carbon to put at your console so you are running your entire environment, but with a different Carbon (or Live) as the 3rd unit.

While I understand you have a battery that should be good, it's worth a test. Sometimes one does fail to meet expectation sooner than it should.... That's why borrowing a different unit as #3 is a good plan if you can - it validates everything else about your system is good.

Ok. My buddy has a Carbon 12 that I can borrow. I’ll give it a try.

If you do that, and the borrowed unit works OK in your otherwise unchanged configuration, you have a very powerful datapoint for Lowrance, leaving them little choice but to agree the MFD is defective.

I might have missed it, but if your buddies works, then try a hard reset on your before sending it back to Lowrance. Could just be some kind of glitch and sometimes a reset will clean it up. Worth a shot and only takes a minute.

So I put the new unit on the bow and moved the bow unit to the left console. So far everything is working like it’s supposed to. I don’t know why but I have a hard time believing this fixes the issue unless someone much smarter than me can explain it. LoL!

Grout-scout had a good point. These units are essentially complex computers. They store persistent data (that doesn't go away when power is cycled), and if there was a bad hiccup, you're suffering from it by flaky action. Let me ask this. When the questioned unit is on the left, are there two ethernet cables attached to it? When the former left unit is at the bow, is there only one ethernet cable connected? If so, move that ethernet cable to the other port on the unit at the bow, and power cycle. Note if it is still OK when you power up again.

Regardless, once done with the above if you choose to do it, do the hard reset that grout suggested, then go back to the original configuration to see what happens.

👍

When doing a hard reset will you lose all the waypoints, trails, etc? If so, what know you can save all that info on a card.

The hard reset will affect only the unit being reset. If the network had been working, the units would have synchronized within seconds of identifying one another on the network after power up. I'd expect that the two original units hold your unique data. You can check the waypoint list, for instance, but will probably find them identical. I assume they are all on a NMEA2000 network, which is where this happens, BTW.

One good thing about a multiple unit system is that it gets much harder to have a bad uh-oh resulting in the loss of data.

After a hard reset, the first time the unit joins the network after power up, it will automatically reload the waypoints from the other unit(s) - if the reset unit is working properly. You can leave your other two powered off while you reset the new one, and that will protect data. I don't remember if routes/trails get synchronized, but would bet they do as a guess.

Thank you

I just edited to mention the automatic synch that saves waypoints is done via the NMEA2000 network, not ethernet. I assume all 3 are on NMEA2000?

Yes they are