Fuel Management not picking up P or S

[kaptkaos]

I have a 2004 Hydra Sports 330 VX which came rigged with 300HPDIs but was switched over to twin 2007 F250 by Plantation Boat Mart. They kept the same Yamaha Digital MFD (Round) guages. I am getting Fuel flow from the Starboard engine only. The meter does not show P, S, or PS regardless of how I press the SET or MODE buttons. I borrowed a brand new known good fuel sender and hooked it to the harness by the fuel filters, and blew through out. It did not register anything on the guage when plugged into Port, it did on the Starboard. The guage never lit up P,S, or PS during the testing.

I am thinking it can be one of these things:

1. Harness
2. Wiring install
3. Guage

I can probably borrow a guage and swap it out to eliminate that, lets assume its not the guage, what should I look for in the wiring? Also, I read that its important for the Yellow wire of the Fuel Guage to be wired to the same Positive as one of the guages ignition, does it matter which one, and would this cause the problem? I mean, whats the difference if they all turn on anyways?

Thanks!

[rodbolt17]

on the FMM, make sure the green/white wire goes to the port engine green wire tach signal and the green to the stbd green wire tach signal.
one tach,the speedo and the FMM should power up on one keyswitch.
they would have had to access the tachs to switch the setting from 2 stroke to 4 stroke and may not have gotten the wires correct.

[kaptkaos]

Rodbolt, thanks for the prompt reply, would it matter which tach or keyswitch? Would the 2-4 stroke DIP switch make a difference with regards to this problem? The fuel burn on the one working motor and rpm on both seem right on.

[rodbolt17]

no, no and no.
will make a difference if the wires were not reconnnected properly.

[kaptkaos]

Thanks for all your help, I found the harness had been knicked, as soon as I repaired it, all began working normally.