confusing ground wire location?

[lpugh]

2B121485
2003 bass cat, cougar
Regarding paddlewheel sensor harness
black/orange wire in harness goes only to pitot/seatemp connector..
Diagram instruction do not show black orange going to fuel/oil tank sensors
Mecury diagrams show black/orange also going to fuel and oil tank senders.

Bass cat diagrams and the boat are wired with the sender ground going to battery negative
Seems the black orange should also go to the fuel/oil senders as well.
Since these sensors are simple 2 wire resistors it may not matter,
I am replacing both fuel tank sensors and the A 10 control panel that no longer switches the 5 volt reference to either tank.
Want to be sure this right before connecting.

Leave it or change it???