Voltmeter Not Working

[Ramsden]

I have a 73 plus 2, negative earth with an alternator. The dashboard voltmeter has recently stopped working and registers no charge to the battery when the engine is running. Despite this, the alternator seems healthy as the battery continues to charge.

Has anyone experienced this before? Any suggested causes/cures?

I should also mention that at about the same time the fog lights stopped working...

All suggetions welecome!

Simon