Discovery 300Tdi, Tachometer not working

[Springer 6]

Some time ago my Tacho stopped working, It was intermittent at first and seemed to be affected when I moved the wiring harness close to the battery/fuse box, but I cannot find a loose wire or connection.

I have read that a failed /intermittent tacho is a sign of an alternator fault, but my alternator seems to be charging the battery ok.

I cannot find a diagram for the Tachometer circuit in my Haynes Manual, but have read that it is controlled from the "W " terminal on the alt. ( white wire ) , is this correct ?

Does anyone have any suggestions or a wiring diagram ?

[Cannonball Bob]

Probably just a loose connection/dry joint on the back of the alternator.

[floyd fan]

On the top of your alternator you will see a white/black single wire, pull the connector of and clean it. Better still replace it with a good quality one.