Fault with 225 Opti

[Doubletrouble]

I have a Mercury 225 optimax (1999) and have a fault with the clocks all reading zero, The engine runs fine but you have no idea what is going on with the revs, fuel, hours, speed etc. I have checked all the connectors and fuses they seem fine, Ive tried disconnecting the battery and reconnecting but that makes no odds.
Has anyone got any ideas what the fault could be? It worked fine before the engine was serviced but I think that is probably a coincidence.

[Burty]

i think all the signal wires and power come from a plug in your control box check to see if this has come out.