Aftermarket amplifier installation

You would need to tap the speaker outputs on the DAC for a signal. It is in the right rear behind the trim. But you may not like the results. The Fusion uses active noise control. IE: it listens to sounds inside/outside the vehicle and then sends sounds in the opposite waveform through the speakers to cancel out the sounds. Not sure what that will sound like coming through a sub-woofer that is not getting the same control signals.