Why doesn't car speaker work?

My rear right car speaker won't work?

• The speakers i put in my car are Pyle PL6984BL Blue Label 6x9 Inch 400 Watt 4 Way speakers. The woofer of the rear speaker doesn't work most of the time. But about once a week, when i'm driving, i can hear when it is working, because i can actually hear some sort of bass from that corner. The woofer is the only part of the speaker that doesn't work. Keep in mind, it does work sometimes, but not all of the time. Is it the speaker? the wiring? Can anyone help me troubleshoot?

• Answer:

  it could just be a loose connection, bad wiring, bad speaker, or too much power going to it so it pops the circuit breaker (if it has one) and when it cools down it resets itself