I recently purchased a used KDC-MP222 and picked up a wiring harness seperately at my local Best Buy. After connecting everything, the HU seems to work perfectly, but I get absolutely no sound. Could it be that the wiring harness I have is not labeled correctly? If I connect a 9v battery to the speakers at the connector, I get a response. The wiring diagram in the manual for the headunit is totally worthless. Please help anyone! Thanks