As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE PREFLIGHT CHECK FOR FLIGHT 4031 THE CREW REPORTED THAT THE EMERGENCY LIGHTS WOULD NOT STAY ON FOR MORE THAN 10 SECONDS. THE CREW FOUND THE EMERGENCY LIGHT SWITCH IN THE COCKPIT WAS SET IN THE ARMED POSITION WITH NO POWER ON THE AIRCRAFT. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE AFT EMERGENCY LIGHT BATTERY IAW CRJ-700 AMM 33-51-17, OPERATIONAL CHECK WAS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.