The CD changer equipped in some Ford vehicles can overheat and lock up, illuminating an error message on the head unit’s display. The original CD changers suffered from an inability to shed heat properly after prolonged operation or when the sun beat down on the dashboard just above the changer. Ford rectified this concern by installing larger fans in the changers, but older changers still exist, with the smaller, ineffective fans. In many cases, you will need to have the changer removed from your Ford and sent to a radio repair shop to have the larger fan retrofitted.
Open the bonnet on your Ford at the end of the day.
Locate and disconnect the negative battery cable from the negative terminal on the battery with the battery wrench.
Wait until the following morning and reconnect the negative battery cable in reverse of how you removed it. Close the bonnet when done.
Insert the ignition key and turn it to the run position. Watch your CD changer to see if it reset. If it did not, take the Ford to your local Ford service department or automotive stereo repair shop to have the CD changer repaired and/or replaced, depending on the extent of the damage.