HELP!!! Replacing head unit in a '96 JGC Ltd. W/ Infiniti Wiring question.

I'm replacing the the factory unit with an aftermarket cd player. I've run into a problem with the Infiniti gold system.
The stock amplifier is giving me trouble. I bought a wiring harness and hooked that all up. With that only my FM works and my cd's won't get any sound . I've read that I need to split the remote wire coming from the new cd player. But where does it go? So I split the blue remote wire from the new unit and connected it to a speaker wire. That resulted in the CDs producing sound, however, I turn up the music and it goes quiet, I think the amp turns off. As if there's not enough power going to the amplifier. The Cd player still plays, but nothing is heard. I've read that i'm supposed to connect to the blue remote wire (from the new cd player) to the "amp turn on wire" on the jeep. Which wire is that? How do I get this thing to work?

Also, does anybody know why the single black wire coming from the jeep is labeled "AMP"? I used it as my ground wire, which I've always been under the impression that black is a ground wire, and it seems work as a ground wire. Please Help?!?!?
-Bud

I replace my deck w/ a pioneer DEH4600 something like that. bought the Harness and hooked up the wires as described in the Harness Directions and Pioneer directions and have had no problems. I have a 94 Grand Cherokee Limited 5.2L, it had the Infinity Gold Series cd player.