If the front/rear speakers are powered right from the head unit, possibly the head unit's internal amp quit, or the Kicker main amp quit if it runs the front/rears. You should get at the speaker wiring and disconnect the amp/radio and test each speaker with a small 1.5 volt battery, each one will click when you apply the bttery power to the speaker. If they are good, you know it's the amp or headunit. How long/loud did you play it?
