Speaker Connection Problem

So this house we moved into already has speaker wires running to their respective locations for 5.1 audioThe guy wired the rear speaker cables through the top of our basement, above the tiles (which I removed on the route to make sure there were no disconnecting wires). I can't see any visual anomalies in the routing either, however I must confess I can't see about 5% of the wiring. I also made sure that the polarity is correct for the connection from the speaker to my system. I did the 5.1 audio test and get no sound through the two rear speakers L + R.However, when I use my own crappier cabling , the speakers work perfectly. I'm at a loss here. Is there a way to test the connection other than hooking up a speaker lol?My system is the Logitech Z-680 systemhttp://reviews.cnet.com/pc-speakers/logite...7-20720043.html