Hi guys,

I just bought another car recently and already has a sound system with pioneer headunit, subwoofer running on an amp.

I swapped the headunit with alpine xda-x100, plug the RCA cables to the back of the headunit to SW, but the sub isn't working at all.

I did the rewiring myself, just matched all the colours.
Everything's working fine except the sub isn't working.

Any idea what's goin on?

Thanks,
Steven