I assume your power is hooked directly to the battery and the fuse is OK? Is the battery at or above 12v+? Some amps won't turn on or protects if the battery voltage is too low or high.
Try removing the speaker wires from the amp connectors and then turning it back on. If the protection light goes away, it means either your wires are grounding out/shorted together, or a speaker could be blown (coil melted fully or partially shorting the windings producing a really low or zero resistance). If the light stays on with no speaker load, then something is probably wrong with the amp.
