Car Stereos: 2004 Impala stock deck rca wire, level outputs, rear speakers

Question
Me and my friend are installing an amp and my subs off my stock deck. After checking the back of the stock deck in my 2004 impala it seems after testing each wire, we can't find the RCA wire. Any suggestions. Thanks!

Answer
Trevor, There may not be any line level outputs from the stereo.  It may only have speaker level outputs.  The easiest way to hook up subs and amp to a factory system, is to splice into the rear speaker wires (near the rear speakers).  Hope this helps, Scott