adding a charging fault light

My mini denso has a 2 wire plug. Plus heavy output to battery terminal.

On the 2 wire plug its labelled IG for ignition in, thats ign switched hot to turn on the regulator,

The other spade is labelled L for indicator light. Thats where the wire from the indicator light goes.

If using an LED these are polarity sensitive, if you hook it up backwards it will not light.