I had a Pioneer DEH-P8400MP Aftermarket CD Player installed in my 99 Mustang with Mach 460. It worked fine for approx. 3 months, then one day it ejected a CD and closed the face (cd player has the bottom flip-face as well as the main screen display) and quit working. It won't turn on or anything. I checked all connections and everything was still hooked up fine. I had an older Pioneer deck that I hooked up to the same wiring harness and it would not turn on either. I checked all the fuses I could find and there were none blown. I used a test light and there is no constant power being fed through the wiring harness. I hooked up a temporary line from the battery to the constant power on the deck, and now the older one turns on, but with the same setup, the newer deck will not. I realize that my newer 8400MP deck may be fried, but cannot say that for sure as it may be some connection. I unhooked my battery for 10 minutes to reset everything, checked all car fuses, as well as the cd player fuse, and have double-checked all my connections. The remote turn on works fine, but there is something wrong with the constant. Is there anywhere else to look for blown fuses, or could it somehow be something else? I am fairly good with stereos as I have installed many before, and have done almost as much troubleshooting as I could think of. Any help or ideas would be greatly appreciated.