UPDATE***
Took the factory radio head unit to a factory radio service shop. The microprocessor and power supply were both dead. The technician stated "somewhere along the install of the new headlights you caused a short which produced a power surge that went into the constant low voltage power lead of the radio head unit (maintains memory). At 22 years old, your components inside are fragile and do not respond well to power surges. Your radio can not be rebuilt, parts not available. Dead. Either upgrade to aftermarket or purchase a used one off the many sites on the web. If you use another model make sure to get the amplifier as the connectors are different."

My buddy who has a 2002 4Runner just upgraded to a touchscreen double din. I took his old head unit and amp and it was plug and play.