There is a ribbon wire that goes from the body of the radio to the faceplate. It my be loose on the pins or failing. There is also a chance that the printed circuit on the rear of the face plate is going bad. You'll probably have to send it in for repair.
RepairPal Certified shops can diagnose and repair your 2001 Ford Explorer. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.