confusing ground wire location?

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???

EITHER ground can be used: BUT NOT BOTH.

Black w/orange is the 5V Ground Reference from the H-Bridge in PCM.

Intermixing a 12V ground and 5V ground on the same circuit WILL damage the PCM 5V circuits.

Late model fuel/oil harnesses do not run the 5V wire out with the Tank-1 and Tank-2 circuits. Battery 12V ground is used instead.

Thanks Don, had to be sure on this.

It pays to be thorough, Thought I had a bad A10 panel, Fuel gauge has never worked on this boat since I owned it, while verifying all wiring to be correct I found the Pink wire for the fuel gauge and the orange accessory wires were reversed in the connector to the A 10 panel. Suspect it has been this way since it was new. Found it by checking switching at pin locations with ohm meter and comparing to Bass Cat diagrams. Glad I caught that, would have instantly damaged the pcm when accessory switch was turned on. Neither wire was connected and did not have the pitot harness connected.

someone needed glasses when harness was assembled didnt they LEON ..... quality control

If you're using Smartcraft fuel level, the pink ANALOG wire should be disconnected and isolated (completely).

The pink wire supplies the 5 volt reference that travels thru the A10 panel which selects the right or left tank and sends that 5 volts to the sending unit which grounded to the battery negative, Right?
It is working that way, both smart craft gauge and vessel view link

When I bought this boat 5 years ago fuel gauges did not work and a PCM did fail, I traced it back to the A10 Panel and disconnected the pink and orange wires at the time, The paddle wheel harness has been disconnected all this time. While repairing the rigging problem I decided to to address this issue further. It does have a Pro XS motor now instead of the 2003 optimax

Rigging hose now moves in and out of the bilge freely as needed, never have backwash issue on this boat so that should not be a problem. If it does not work out, I will bring it in from the side as suggested. Custom built flange in the spashwell, upside down version with offset


Attachment 523507

That's much better.