Charging loom

[Sean Mooney]

Could anyone help me with what this plug is for on the charging loom ?

I removed the old engine that long ago I can’t remember what it was used for.

Ive fitted a b204 and just want to make sure I don’t need to connect it to anything

 

[Varnis9]

Already replied on facebook post, as said black is switched live to ignition, red is permanent live 12v.