Your RCA Adapter should have Instructions On it or With it.Usually it needs to be spliced into the Positive & Negative of the Speaker wires of the Front or Rear wires.
12v Constant =white Ground =black Ignition =purple Illumination =gray or red/black Factory Amp Turn-on =lt. blue Power Antenna =gray LF Speaker =lt. green +LF Speaker =pink -On vehicles with the amplifier, the LF tweeter wires are red (+) - green (-). RF Speaker = gray RF Speaker =brownNotes: On vehicles with the amplifier, the RF tweeter wires are pink (+) - blue (-). LR Speaker =yellow +LR Speaker =brown -RR Speaker =blue + - RR Speaker =orange -Notes: On vehicles with the amplifier, the subwoofer wires are green (+) - red (-).
If you are putting in an AMP, I would use the Rear Wires. You can get them at the Speaker Harness of the Rear Speakers or Behind Radio:
LR Speaker =yellow +LR Speaker =brown -RR Speaker =blue + RR Speaker =orange -