Sub not working

i have the same problem with my sh*t bahn, you fried the voice coil! or the former seperated

So would it be worth it to repair or just throw away? How do I know what happened to it.  Some A@#$%^& sold it to me like that I am so pissed. 

If your sub's cone will not move, the voice coil is fried.  There are a number of ways this can happen, but the most common are 1) defective speaker, 2) overpower, 3) overpower due to amplifier clipping, 4) wrong enclosure.  It can be repaired by re-coning the speaker, but the cost may be more than a new speaker.  Check with a loudspeaker re-cone service.  Start here: http://www.recone.com/

you couldve also underpowered it because mine did it from being underpowered by a damned sony amp---- 1996 Chevy S10 ----

1 Lightning Audio S2.600.2 Amp

2 Lightning Audio 12" Subs

1 Lightning Audio 1 Farad Cap

"Underpower" will not harm speakers, this is a myth.  BUT, if you use too small an amp or too cheap an amp and try to compensate by cranking up the gain, you can drive the amp into clipping which CAN harm speakers.  Thus the idea it was underpower that did it.  It is clipping, not too little power.  Too little power by itself CANNOT under any circumstances on earth harm a loudspeaker unless the amp is clipping, period.

A lot of car stereo shops will lie to you and try and tell you it is dangerous to "underpower" a sub, because they want to sell you larger, more expensive amps.  It is complete BS.  I design professional sound systems for a living and can tell you we always use a 3X to 5X safety factor in our subwoofer designs, meaning if the SPL we want to achieve requires 500 watts of audio power, we use subs rated at no less than 1500 watts RMS so we know we won't blow them.  Underpower does not harm speakers, over-power or DC from a clipping amp does.

well i run equal power RMS on amps and subs so i think i should be good right?---- 1996 Chevy S10 ----

1 Lightning Audio S2.600.2 Amp

2 Lightning Audio 12" Subs

1 Lightning Audio 1 Farad Cap

As long as your gain is set correctly for the signal level you are giving it, yes, you should be good as long as you are using equipment from a reputable manufacturer.  Lightning tends to give really accurate ratings for their components, so you are fine as long as the amp is not clipping.