. Seriously, usually a bad connection in the cluster, either a ground or the lead for the tach or the multi connector plug. Did it quit suddenly or die a slow death?? I'm not 100% sure, but I think the tach picks up its signal from the ECU. The tach itself is nothing more that a fancy voltmeter. You can check it with a digital low voltage multimeter by checking the resistance across the two leads for the tach. Should not be zero or infinite.
1987 BMW 325
[This message has been edited by jeffsr (edited 06-13-2000).]