Random battery light comes on and brightens up whole dash?

[slappedvr]

hey guys
the last few times ive driven my vr commodore the battery light has come on randomly when im driving and the dash brightens up and theres a small whistle coming from the engine. The battery light does go off and everyting returns to normal but what is causing this and how do i fix it?
cheers

[RX25SE]

Sounds like the alternator is on the way out.

[slappedvr]

the alternator is on its way out or the regulator?

[chrisdoesitbetter]

the regulator is on the way out... genuine bosch $65 from repco