I spent hours trying to track down a way to hard wire an after market stereo to a jk wrangler sport with the infinity 6 cd interchanger hu and amp. (has two cables going in the back not the usual one. ). Got the hu to power up but no sound to speakers. I know I could use a metro harness but have opted not to go that way. To which cable do I solder my aftermarket huvblue amp power cable. ?