Fuel gauge plug/unknow wires?

[mleads310]

Just a quick recap, I’m doing a repower and I’ve removed all the old harnesse which were for Yamaha round gauges. Totally forgot about tracing the wire for the sending units for the fuel tanks. I was able to locate them. They go to a switch panel so you can switch from one tank or two tank which is normal from the factory


Out of that switch comes one pink wire, and then a dark blue and a black wire which are both grounds. They go into this plug.




Since this plug is a factory plug, my question is what else did I disconnect because there’s three other wires (two baby blue and one dark blue)?

 

[mleads310]

Ok it looks like it plugs directly into the old yamaha round tach, still not sure what those three other wires are for? I don’t wanna loose anything. Is it possible for the sync function?

 

[mleads310]

OK, I’m an idiot. Those two connections don’t go together not directly anyway. But I did find out is that the six pin out plug that has the baby blue wires on it is the factory plug, and only three of those wire wires were used on my boat. The pink, the black and one of the dark blues were used as two grounds and one signal for both of my tanks. The reason for one signal is because for that plug, it comes from the helm switchboard and at the helm switchboard both signals from both fuel tanks are then converted to one signal coming out and depending on which way you have the switch will tell what tank the signal is being sent from.

 

[SkunkBoat]

Dark blue would normally be cockpit lights. gray would be the NAV (red/green) bow light

 

[mleads310]

Appreciate it skunkboat, I overlooked the obvious in my original post. In my head the factory 6pin plug (with the 2 dark blue, 1 black, 1 pink, 2 baby blue wires) plugged directly into the old original round Yamaha fuel management gauge/harness (purple, orange, black,red etc). It obviously doesn’t.

Apparently on my Grady, the four wires (2 signal/2ground) from the 2 fuel sending units go to the helm “fuel” switch. From there only 3 leave (2 ground dark blue and black/1 signal pink)…. Not sure why 2 grounds tho). Those 3 wires end up at the factory plug I posted above (notice that plug has a 6 pinout tho).
That plug was connected to Yamaha gauges thru a slice connection(shown here)
The other 3 wires in that plug (1 dark blue and 2 baby blue) are now terminated after the connection (pic above)and are not used. Now before I realized that those 3 wires were terminated after the connection, I was worried that they were needed for something and I didn’t want to want to screw something up.

For reference here’s the old connection as a whole now removed.