Burzu, if the red light is on, it could mean you have a bad ground bro.......check your ground wire. Was it working before? if not, check your signal wire as well as your ground wire. What settings was it on(if you said it wasnt working before)? check to make sure all your settings on your amp are zeroed(minimized), and reset the systemby disconnecting all power to it(easiest way is by disconnecting your battery, turn your key on, which drains the system entirely, then shut your key off and reconnect the battery).
If none of the above fixes the issue, take it to an audio shop.