As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ALL 4 OVERWING EMERGENCY EXIT SIGNS WOULD ONLY ILLUMINATE FOR 15-30 SECONDS BEFORE TURNING OFF WHEN THE COCKPIT EMERGENCY LIGHT SWITCH WAS PLACED TO ON. REPLACED THE BATTERY PACK, NO HELP. REPLACED THE POWER SUPPLY/CHARGER AND THE SYSTEM OPERATED NORMAL, MFG P/N OF CHARGER WAS 2012-1, DPN 333780101, S/N OFF28335.