FG 300X4 Amp Hook up Question for Rear Speakers

[1fathog]

I have a 2010 Ultra and I would like to also hookup my rear 4ohm speakers to the RF 300X4 amp and I am confused.
I looked at my service manual and still dont get it.

First off, can I cut the rear harness and run the wires from the harness to the input side on the amp and hook the ones from the rear speakers to the output side on the amp?
And will my fader still be working?
Any help would be greatly appriciated...

 

[gusotto]

Not familiar with the FG 300X4 amp.
Unless things have changed, I think the speakers are 2 ohm. Not 4 ohm.
That's the way it is on my '07 HK radio.