Car Stereos: subwoofer question, lowpass filter, bare wire

Question
Okay the subwoofer I have is Kicker 05DCVR104 and the amp is Kenwood Excelon KAC-X541.  I installed them both a while ago, and am taking a renewed interest in trying to diagnose the problem I'm having.  My subs aren't putting out almost any kick at all.  I can hear a small amount of bass coming out of them, but it's almost nothing.  The amp is getting juice so I don't think that's it... when it started malfunctioning the subs would sort of kick in an out, but then they basically stopped producing any bass.  Any suggestions?

Answer
Joe, If they did work fine at one time, and now they are not working as well, means something got messed up.  If they intermittently went out, it probably is a short inside the amplifier.  Perhaps there is a lowpass filter that shorted out.   More importantly, it is a good idea to check your wiring and make sure there are no places where bare wire is showing.  Hope this helps, Scott