I had that same problem no too long ago. When my mom had the car she had circuit city put in an aftermarket head unit with some kind of fancy adapter that supposedly let the system use the factory amps (which I'm not sure if they were really working or not). Well, I got the car and my speakers were going bad, so I decided to get a new system and was going to try to use the existing amps. I got the wiring scematics from a dealership, but I still couldn't figure out a thing. The factory amps are a pain to do anything with, so many wires and crap going to them that don't match up. I ended up just getting a new amp for the system. But I would have to agree with sho nick, you would be best off to go to an audio shop to look for connectors, but you still may not be powering up the amps. Good luck.