1999 ox66 225 Shows Zero on Tach

[tunacity]

I have a factory Yamaha tach that started working intermittently and then stopped reading rpm - reads zero.

I'm looking to trace back wires and connections to clean connections and can't seem to find which wire leads from the ECU.

Could someone help me to get a sense for how this all connects and/or a recommended progression to clean/test the wires?

Many thanks!

[robert graham]

Double check connections on back of tach, and fuses, which can get a bit of corrosion on their tips.

[tunacity]

Yamaha Tach Reading Zero on OX66

Thank you. I will start there. I hit the connections but not the fuses.

I should mention this is a new tach and the problem started before I made the switch. This is why I was thinking there might be an engine side issue.

Double check connections on back of tach, and fuses, which can get a bit of corrosion on their tips.

[tunacity]

Green wire on port tach reads 6 volts.

No reading on green wire to starboard tach that is not working.

I'm trying to find a wiring diagram that matches this model.