testing the rpm gauge

[NineEleven]

Hi guys, I got a problem with my gauges. The water temperature, rpm and fuel consumption gauges don't work.

How do I test the rpm gauge with a multimeter or battey (1,5 V..)
I tested the water temp with a 1,5 V battery and it works. The problem is in my SI board I think.

I drive a 88 euro 316 m10

[Gregs///M]

You test the temp gauge with a digital square wave generator.

However, your right about the SI board. The SI board controls the tach, temp, MPG, and service lights exclusivity. Any or all of those not working is surely dead SI board batteries.