I had my battery disconnected in my GT while I was doing some work on it. After hooking it back up my radio would not turn on (not a mac). I consulted the service manual to see if there was a security feature that disabled it. The only thing mentioned was to check the voltage at the svc. block (not fun). I emailed some associates at the Ford dealership and no futher info was gleemed. Not wanting to jack with the elec. svc. block I pressed some of the buttons on the radio to see if anything would respond. When I pressed the CD eject I could tell the radio was trying to eject a CD (but still no display). I decided to insert a CD and whala the unit came back to life and works fine now. Go figure....