No Tahco Reading

[inosnt]

I have a multifunction tacho (6YR-W0035-E2-00) that is no longer working.
It has power etc and everything but the rev counter is working, it just stays on zero. I run it in the lake anmd on the muffs and have had no luck, I had removed the both speed and tach before puting the boat into storage over winter while I made a new dash panel. I numbered all the wires as I unplugged them and double checked I had them in the right place when I re-installed them so am unsure as to what the problem is. I started it today on muffs and breifly had a rev reading but that soon disapeared and hasn't done it again.
If anyone can please help me or has any ideas it wuld be much appreciated.
Also if someone has a wiring diagram for the tach + speedo with a 703 control box so i could triple check I got it right i would be appreciated.
Not sure if you need to know but I have a 1991 ProV 200.
Thanks

[200090tlry]

Im still trying to figure mine out

But if yours worked in past try and turn number thingy on back of tach sometimes they loose metal contact and twist it back to same setting see if it works again. If the weather warmed up id give mine a start and try figure it out. Another thing that can go bad is regulator have you crossed battery posts.