My jvc sound bar th-s301 can't connect to the subwoofer but before was working fine.

SOURCE: JVC TH M505 Subwoofer not working

i need to find the wire that connects from the subwoofer it has like little spikes inside the medal part and the spikes broke off

SOURCE: JVC Subwoofer problem.

You may have a break in the wire. You can find out by slowing moving your fingers down the wire until you notice sound coming from the subwoofer. You can fix it yourself by cutting about an inch away from the break both ways. Then cuttings some of the wire off, so the copperwire is exposed. then wrap the two copperwire ends together and seal it with elections tape. or Try replacing the 60 watt subwoofer wire.

SOURCE: Connecting Powered Subwoofer to a Receiver

you will need a line-level converter to use this subwoofer- it is a rectangular-shaped box with wires coming out on one end and red-and-white RCA plugs one the other. The end with the wires coming out will hook to the receiver, and the other end will need to plug into the sub.

SOURCE: JVC - Problem connecting a Powered Subwoofer to a Receiver

Have you set speaker setup configuration to SUBWOOFER YES? Also check SUBWOOFER OUT ON/OFF button on the front panel.

SOURCE: no sound in sound bar and subwoofer

for Jameslicon re wireless sub going on and off repeatedly. Both the soundbar and the sub have 4 wireless channels - try a different pairing of those channels. There is a sliding switch on the back of both units. I set each of mine to channel 4 and the problem went away. There is also a signal level switch with 3 levels on the back of the soundbar. If the wireless channel idea does not work, try a different setting on the level switch. Good luck.