(1) Welcome to CT!
(2) Do you mean the head unit itself isn't lighting up, or that all the dash lighting has been knocked out?
(3) If the orphaned green / red and white / green wires were originally attached to your factory head unit, those are the illumination wires for the head unit alone. Their being disconnected shouldn't knock out all the dash lighting (unless you've caused a short or something ...).
(4) If, on the other hand, those orphaned wires are the ones linking the entire dash lamp set with their power source or the dimmer rheostats, that would explain all the dash lighting being disabled.
(5) Here (attached) is the 2001 tail / dash illumination wiring diagram.