amp gets power, speaker doesnt move.

Ive installed a few basic systems, just head unit w/components and subwoofers.  most work great and recently i had a 15 kicker L7 on american bass 80.1 1000w rms amp and a 12 american bass XD on an 800w sony xplod amp. worked great for about 6 months and the xd that i had for a year blew as i turned volume up from 0. L7 still worked fine for a day, then when i took the XD out and turned my truck back on there was no sub. the amplifier still had a green power light but the sub wouldnt move. i just installed a power accoustic mofo w/ a 2000w BAMF series power accoustic amp in my friends car and the same thing happens. amp gets power, but speaker doesnt move. this speaker just worked 4 days ago in a mutual friends car.

Any help or ideas anybody has would be inexplicably appreciated.  

If your getting no sound check your speaker wire i run 8gauge on my l7 if its not that check your rca they might have went bad