XFader NOT Broke 
I am not at all hard on my cross fader, and all of a sudden it will only shut off the left side (Deck A/C). Deck B/D are always heard and the on air light will not go off for that side.
Yes I have recalibrated, rebooted, etc. Seems like a hardware problem, and guess I 'll have to ship it off after a wedding I have to do next weekend.
Sorry, just a little bummed and had to rant. Gonna suck waiting for it to come home too.
Edit: See my next post down
B/D are still assigned to the right side, right?
On the bright side, might be a good chance to try that innofader mod
Yes B/D still routed that way in audio set up, is there anywhere else they can be unassigned? CRAP I FEEL SO STUPID RIGHT NOW AAAARRRGGGHHHH
I couldn’t tell you how it happened as I never have the cross fader panel even open in Traktor, but the decks were off in the cross fader panel. I didn’t even think about it being unassigned in the xfader section, because I never have it open.
Thanks for the intervention Padi!
I still feel stupid though
How the fudge did that happen.
Edit: I must have had shift down when I hit the fx buttons in the mixer section last time I practiced. I have, so far, always just left the assignments alone and after reading about it once when I first got the S4, I forgot it was even possible, lol.
That is what I meant by assigned to the right side 
Glad you saved yourself the hassle of having to send it back.
Just a blonde moment as my wife would say. I call it a brain fart.
We’re learning every day!
But doesn’t the S4 have LEDs below the volume faders signifying which side of the crossfader the deck is assigned?