As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY LIGHTING: ALL THE EMERGENCY LIGHTS ASSOCIATED WITH NUMBER 4 BATTERY PACK ARE INOP. GAINED ACCESS TO AND REMOVED AND REPLACED #4 EMERGENCY LIGHT BATTERY. CHARGED BATTERY AS CHECKS GOOD.CLOSED UP ALL. ACCESS. IAW CE680 MM 33-50-10