Tach Quit, Speedo and Odo still work...
 

Alright so i was driving today my tach randomly quit, was working fine before, and as i was going through a parking lot it just quit and now rests on 0. When i started the car back up again after letting it sit the tach worked... for aabout two blocks then quit then, spent a full hour on the search on here already and couldnt find anything on just the tach. So if anyone can help, please :)
Its on a 92 JDM RHD RX-7.

About five years ago my tach took a dump. I changed it a couple of times only for the new tachs to break within a few hundred miles. Sometimes when the coil pack malfunctions it can take out the tach so I looked at that for possible causes but to no avail. My fix was to replace my whole cluster as I had short somewhere that was frying things.

I contacted fritz and he sold me one for a very reasonable price.

Go behind your ECU locate the yellow/blue stripe wire and connect a test light to it.

If you have power there it means you have signal coming from the coils .

Next remove the cluster and inspect the cluster behind the gauge itself look for shorts. Theres quite few threads on cluster removal and capacitor failure .

I couldnt find my tach issue so I ran my aux wire off my standalone directly behind the tach . removed the right screw out of the 3 thats behind the cluster and tap it there and now my tachs are even better than before.

Good luck!

Thanks Alex and Montego, today is my day off so I will try testing with the test light as you say Alex then back track my way to the clutster like you say. Hopefully nothing but when is it ever nothing right?