Couple of day ago my sub was working fine then one i try listening to it but ther wasnt no sound coming out the light on the box still change color as if the sub was working what cuold be the problem i got no idea??

Probably complete failure of the I/P dimmer

sounds like a bad mainboard

Yes one of the relays could be draining the battery.
I would open the fuse and relay boxes and try to find where the noise is coming from. If it is a relay, pull it out and see if the noise stops.

1.Check the input cable or change it and see the result.
2.Test the subwoofer to a computer.

You can prove the sub pre-output works by running an RCA cable from it to the input of a tape deck, TV or any other device that accepts Line In and will either display it or play it. Test it on VERY LOW volume at the receiving device.

Different sub pre-out cable?

Sounds like you have no signal going to the amp. Check th RCAs.

How about trying with its internal speakers ?
if it works fine then the sound output jack-port have a problem.
If not working then try to re-install your audio drivers.
If still not having good result even if you re-install your operating system, you should go to repair center since you have a hardware failure.

Check the fuse on the amp.

My girlfriend had the same thing, light was on, no sound whatsoever. The fuse on the amp had blown, but I'm guessing some current must have made it through to just put the light on. Make sure you have a 40 amp fuse in it, that's what it needs.

Good luck

try your hardest

The RCA inputs to the sub may be unplugged or damaged. Check them both for the sub and for the amp