As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY LIGHTING: WHILE CONDUCTING THE POWER ON CHECKLIST WE DISCOVERED WHEN THE EMER LTS ARE PLACED IN THE ARM POSITION, THE LIGHTS DO NOT ILLUMINATE. WHEN THE SWITCH IS PLACED IN THE ON POSITION, THE LIGHTS WORK. // SIGNOFF // TROUBLESHOT AND DETERMINED FAULT TO BE CAUSED BY A FAILED #1 EMERGENCY LIGHT BATTERY PACK. REMOVED P/N CBS28·1 S/N·598SM AND INSTALLED REPAIRED P/N·CBS28·1 S/N-007288 IAW CESSNA 680AMM 35-50-10. OPS CHECKS OK