Audio Systems: 98 Mustang Mach Audio 460 Head unit upgrade, wiring pinouts, wiring harnesses

Question
Hi,  I'm trying to upgrade my 98 mustang gt convertibles mach audio 460 head unit to an aftermarket JVC one. I've been having trouble with wiring harnesses and whatnot. I've managed to get a wiring harness that looks like it fits, but when everything is wired up, my new head unit powers on but i am not having any audio output. Is there anything you know i can do/try to get this new unit working?

Answer
Basically the harness must be wired correctly.  Car installation is not my thing and I know that there are an almost infinite number of different harness wiring options.  Since the wires are already run, you may want to check with an installer.  They would have all of the wiring pinouts for the various radios and harnesses.
Good luck.
Dan