What does the actual fader switch do?

[IS300E30]

I have the stock premium sound with the fader switch. What does the actual fader switch do? Does it change the volume output from right to left or from front to back?

If I turn it all the way to the right where does the sound transfer to and if I turn it all the way to the left where does the sound transfer to?

[AndrewBird]

It changes things front to back. I think all the way left is to the rear, but don't quote me on that. Should be obvious with the stereo on.

[george graves]

fader is front and back
Balance is left and right