Audio Systems: Hooking up an amp to a factory deck, level converter, empty hole

Question
Hi, I want to hook up an amplifier to my factory deck.  I know that I have to run the line-level converter, but I'm not sure what to do about the remote turn on.  What should I hook the REM wire up to in order to get it to work?

Answer
you can use the cable to turn on the electric andtenna  that will also turn on the amplifier  
this cable is in the back of the radio sometimes they don't put the cable  but you can test with a meter on every empty hole in the plug until you get 12 vols when radio on