Connecting a amplifier to my factory radio

For a remote turn on in a factory system, just find a circuit in your fuse box that turns on and off with the key and run a wire to it for a remote signal.  Use a voltmenter to test the circuits.  That's the cheap and dirty way to do it.

There are 2 methods of doing this.. One is doing what the above post says and check for a switched 12v wire and using that.. or just tap into your power for your head unit. OR go old school and install a switch that will turn on your amp when you want with a hot wire (live current at all times)

Dont mean to double post but that other one wasnt to clear.. Use a light tester and find the wire that turns on and off when you have your key turn to on.. Then take a volt meter and make sure it has a 12v current running to that.. Then tap into that. They make nice lil wire taps..use those try not to cut the wire.. viods your factory warranty, thats even if you care about that or not.