Okay, here's the deal:
I've had a Panasonic head unit for the past year. It's worked in my '95 ford taurus then it was moved into my current '03 Sunfire.
I got the harness and the GM Class2 chime retention interface. I hooked it all together, soldered the wires together and protected them with electrical tape. Plugged everything together and it worked fine.
For a year it worked fine....
Then suddenly it started giving me issues like one day it wouldn't power on at all (when this happens I lose the door chime/key-in with door open chime, ect..). Then suddenly the following day it would work properly again, chimes and all.

The odd thing is that sometimes the unit will receive power but the chimes won't work. When in this state the head unit won't turn off when I open the driver door (It normally does when the chimes are working), so I eject the faceplate from the unit so its not brightly lit at nighttime from the LCD.
Anyways, it was in that state when I had it half-working last. I had to do some engine work on it so I disconnected the battery for a brief moment. When I reconnected it the head unit would not turn on (yet it was receiving power).

So to troubleshoot I went out and bought a new GM Class2 CRI, that didn't make a difference. Then next I bought a new head unit (Sony Xplod thing with iPod USB input... Seeing as i needed to upgrade from the old anyway, also assuming that the previous head unit was broken) and that too didn't make a difference. The new head unit receives power cuz I can hear the motor for the CD laser pinion track moving as soon as I plug the harness in, but I get nothing on the LCD display (even after resetting the head unit like the manual says.)!
This is super frustrating, I've tried just about everything I can think of to get this working... Fuses, checked. Wiring, checked. Whats even more annoying is that it used to work till problems started coming..

Anyways, I hope someone can help me. I'm compensating for no music with really crappy iPod speakers that run on 4 AA's.

 

Ignition key wire possibly split or broken to the harness or the GM Class2 chime retention interface?

Does hooking it up directly to the battery work? Of course it won't turn off with ignition but it should play toons.

 

run the red (acc) to a source that gets power when the ignition is on such as the ignition fuse at the fuse box