As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L/H AND R/H EXTERNAL OVERWING EMERGENCY LIGHTS INOP TROUBLESHOT PER CRJ900 FIM 33-51-00-810-806. SWAPPED BATTERY PACKS 1 & 4. NO CHANGE. CHANGED BATTERY 4 HOLDER ASSY AND BATTERY. NO CHANGE. RETURNED BATTERY PACKS TO ORIGINAL CONFIGURATION. DEFERRED. CLT MX FOUND CONNECTOR J337 AND J396 DISCONNECTED. RECONNECTED CONNECTOR AND REPLACED #3 EPSU BATTERY AND CHARGER. OPS CHECK GOOD.