Need help with dead tach, 300E
 

My tachometer died a little while ago. Before I pull the cluster out, does anyone know how I can check whether the gauge is getting a proper signal? I know there is a position sensor on the flywheel, and on the harmonic balancer, but I don't know where they go, or whether to measure the signal using volts, etc.

The shop manual doesn't appear to have wiring information for the tach, or at least not that I could find.

Thanks,
Anthony