What was found
DCA - THE TEST OF THE EMERGENCY EXIT LIGHT SYSTEM FAILED, FAULTING EPSU EXT LOAD L ON THE FORWARD CIDS PANEL. MAINTENANCE REPLACED THE AFT LEFT EMERGENCY POWER SUPPLY BATTERY, WHICH DID NOT FIX THE PROBLEM. THE AIRCRAFT WAS RELEASED ON MEL. SUBSEQUENTLY, MAINTENANCE FOUND AND CORRECTED A BENT PIN IN THE AFT, RIGHT SLIDE ELECTRICAL HARNESS. OK FOR SERVICE.