I second Paul100's suggestion to visit the
www.sharememory.com/radio as a good start especially for Explorer radio problems. Sharememory has a replacement board w/ excellent/complete instructions on radio removal and board replacement, most folks can do this with minimal tools. From my web research the Explorer radios had significant display problems.
Another common audio unit problem in Ford cars and trucks is the Ford/Clarion OEM 6 CD Dash unit that has had significant problems with the CD mechanism. Unit displays CD error messages from internal jamming or sensor failure.
These trouble prone units sometimes show no CDs installed when in fact there are CDs present and also not ejecting of nor accepting new CDs when openings exist likely due to dirty sensors.
We are/were having problems with our barely-used Ford OEM 6 CD unit in a 2002 F-350 and I was in the process of removing this double DIN unit from the dash today (with the DIN extraction tools) when the CD door moved a bit. I inserted the ignition key and allowed the unit to power up and it started working/properly ejected all CDs. Possibly flexing the case released an internal jam???
Anyway I'm awaiting the ultimate dreaded OEM FORD 6 CD player problem to present itself (again) possibly w/o a happy ending. Today the unit works - tomorrow - Who knows?!?!
Haven't had much success w/ the searching this Forum so don't know if there are other posts on Ford OEM 6 CD problems . This has been a big OEM FORD audio problem for years and years BTW.