Originally Posted by RonRizz

first and foremost, LOOK and see if the amp is lit up when key is off. if it in fact is, check the stickies here, there are diagrams of the factory harness in a few of those threads. you should be connected to switched 12v, not BAT + In an aftermarket harness ( as in coming off an aftermarket head unit, they are typically blue, or blue with white stripe)