I have a two channel loc. It has a set of wires for the left and right speakers and it also has one black wire. I was wondering if this wire was a ground? In that case I would need to ground it to the body. Thanks to who ever helps me!

 

My Navone LOC says to use the ground only if my amp inputs require it. Otherwise you shouldn't use it

 

Ok, well I installed the amps a sub but in am not recieving any sound out of the sub woofer. All the speaker wires are ran correctly and the amps are recieving power. I changed out my rcas but that didn't work. Would it be the loc hocked up wrong? I have tried it with the ground wire grounged and with it not grounded. What sould I do?
SOMEONE PLEASE HALP ME!!!