Are you hooking it up to an appropriate power source? Are you hooking up the power to the power and the ground to the ground, Is the speaker in a box or car panel, if so you may need to take it out to look at the outlets built onto the outside of the speaker to make sure they are not damaged or broken. Other then that the only other thing you can really check is if the bottom of the speaker is still magnetic. If there are any cracks on the actual speaker and when you lightly push it in do you get an audible bump sound.