2006 Civic Si amp turn on

Have a 06 Civic Si and Installing a Kenwood amp with speaker level inputs and a kicker L7 12. What he wants, amps sucks though. Problems is, since Car is new, can't find dash removal instructions to get at factroy amp turn on. Ran a wire from fuse block from radio, but when radio turns off, Like on a normal radio, the 12 remote turn on is still getting 12v, like I didn't even turn it off. Causing horrible sounds from sub. ANy one have ideas on getting factory radio out????? or where else I can get power from?? tried amp fuse and it stays on all the time, whether car is on or off. . Any help would be greatly appreciated.

You guys are amazing. Thanks a bunch