While driving, all of a sudden the tach stopped working. I checked all associated wiring and connectors but can't see anything obvious, so I'm about to pull the tach out to see if the problem is in the instrument. Does anyone know what kind of signal the tach receives? i.e. block, or pulse? Thanks!
Update: I took the cluster out, still no obvious errors. The tachometer has 3 wires connected: black, brown-black and white-green. I would imagine the white-green to be the signal wire, but resistance measures zero on more than one pin on the connector. @Qavion, would you be so kind to provide a link to your diagram 'Ferrari 456 Instrument binnacle wiring hookup diagram', as the links on this site don't seem to be working.
final update: Apparently the fault was caused by a poor connection on the instrument itself. I fiddled with it, reconnected the cluster for test/measurements but when I started the engine the tach was back online. If only all problems were as easy as this one...
Yeah, I lost the ability to store files online. I use a free version of Dropbox now, but the links expire in 6 days. The tachometer on a 456M uses crank sensor data from the right Motronics ECU. The data is sent on the brown-black wire. White/green is simply the power wire (to all the instruments) from fuse 20 (Instrument fuse). That diagram you requested mostly refers to the digital display. Here's the diagram you needed: https://www.dropbox.com/t/gDrwaiQTRoqaxiDA
Many thanks, that was indeed the diagram I had in mind. I'll download and keep it for future reference as for now I don't need it.
