How are the fuel gauges wired??

[Beyond A Wake]

After I dealt with the batteries I now also lost the fuel / tank information. I have only one gas tank but also a diesel tank for gen. Both gauges are dead.
so I go on Raymarine and the tank is listed and shows total volume in setup. But no info on current level. Also the diesel tank which gauge is in the panel whee the gen controls are is at zero, essentially dead.
the only thing that has changed is that I removed and replaced the batteries twice. All else works now well.
so my question is how are the fuel senders wired and how are they connected to the Yamaha CL 7 or the raymarine through the network nmea 2000 I assume but is there a box in between and why would both be dead?

have not yet contacted GW but that is next.

h
ps this is why we have boats, to have something to fix..............

 

[SkunkBoat]

If the grounds to the tanks are missing the gauges will not work. Possibly wires never got back on batteries?

 

[Beyond A Wake]

Thanks, that is what I suspect and after all I've been through with this it is strange if there still are some leads that are hanging loose. Back to deep dive into battery cubby.

 

[Hookup1]

 

[Beyond A Wake]

summary;
self inflicted problem. When removing batteries to check them out then replacing them in the dark, things go undetected. #4 battery has connected to the negative pole a couple of wires tied together. It is hard to see what is going on in the back of that battery and as it has it after already once detecting that #3 battery negative bus connection had come loose, removed all and put together now this little clip had been left loose.
so now all good and YES IT WAS A GROUND WIRE that was loose.
all good and now I know what all connects to the batteries.........

thanks for all advice in both related cases.

h