Oddball44

I just set up my Klipsch speaker system I got from Walmart and although both my left and right speakers work fine, my subwoofer is not working. I have tried reseating the 9 pin serial connection and trying different power outlets as well as ensuring the subwoofer's knob is turned up where it needs to be. I have also tried to see if maybe using the AUX input would show any different results but this has sadly resulted in nothing as well. Does anyone have any suggestions on what's up?