If you mean it is totally dead, first check the fuse for the memory circuit. It will be tied in with something that is always hot such as dome lights, horn, or possibly the cigarette lighter. Next check the fuse for the switched power. If the fuses are good, check for the presence of 12 volts on two wires in the electrical connector. One will have it all the time and one only when the ignition switch is on.
If the radio has sound but no display, that is a real common problem with Ford radios and real frustrating to repair. I've repaired many for that problem. Since this is always an intermittent problem, I let them play on my test bench for two weeks to be sure I found all of the problems.
Saturday, November 27th, 2010 AT 4:51 PM