As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6389 - PHX-YUM - DURING PREFLIGHT INSPECTION, CREW REPORTED THAT THE EMERGENCY LIGHT SWITCH HAD BEEN LEFT IN THE ON POSITION OVERNIGHT AND ALL THE POWER SUPPLIES TO THE EMERGENCY LIGHTING HAD BEEN DRAINED. MAINTENANCE CONNECTED THE GPU TO THE AIRCRAFT AND CHARGED THE BATTERIES, OPS CHECKED GOOD. AIRCRAFT WAS RETURNED TO SERVICE. (M)