I went to a junk yard and got the optional instrument cluster from a Beretta. It looks exactly identical to the optional instrument cluster in my Corsica's owners manual. Everything works fine as I can see except for two things:
Oil Pressure gauge and Tachometer.
With the OP Gauge, it stays down when I put the key into start, but when I start the engine, it shoots up beyond the red-line and stays up there.
The tachometer simply doesn't operate.
The voltmeter works perfectly fine, speedometer, fuel and coolant temps work perfectly fine as well. I'm pretty confused as to why the two gauges don't work.
Here's the YouTube video of my instrument cluster:
http://www.youtube.com/watch?v=SJx-R2Kenk0