First of all, check your fuses on the amp, then in your car. If none are blown, then check all wires (Pos, Neg, REM, RCA's, and so on) to make sure nothing is loose. Check wires inside your box also. If nothing seems wrong, take a gander at the wiring on your head unit and make sure RCA's are fully connected. Also, check the fuse on the HU too. If none of the above are the problem, find a volt meter and see if your amp is receiving power. If none of the above are the problem, then bring the HU to a local dealer and see if there's something wrong internally with the unit.