I have searched, looked in my Haynes, and tested various wires. The car is an 05 Sunfire with regular CD player. I'm trying to find out what wire on the headunit to hook up the amp turn on... any help
I don't know of any wires on a stock H/U that will activate the amp except for the accessory/ignition wire. This is the wire that tells the radio to turn on when you turn the key, the radio/accessory fuse in the dash will have the same effect, however you will not be able to manually shut off your amp unless you add a switch to the remote wire, which I would reccomend, a small simple toggle switch would do the trick. Most aftermarket headunits have their own amp wire so that you can shut off the amp with your headunit, otherwise they can use the power anteanna wire as an alternative. Hope this helps!
I believe that "module" is doing the exact same thing that what I suggested will do. Basically just a relay that can use any of your stereo wires to trigger your amp. This would be better for getting rid of on/off noise that you will probably get from direct wiring like I suggested at first. Either way will work but that module should make for clearer on/off transitions. I didn't know they made that honestly, looks like a good product as long as it lasts.
the amp turn on is a switched 12 v, i believe that's either red or orange wire
but you can always tap to any other wire like that such as ignition, accessory (such as lighter) or any other one..
Bah I was afraid of that. Switch it is
Just go to Radio Shack, pick up an "add-a-fuse," plug it into the ignition fuse blade, re-insert your ign fuse and another fuse for the power wire to your amp, then run the wire TO the amp...done.