What was found
FORWARD CABIN EMERGENCY LIGHTS DO NOT ILLUMINATE WITH THE SWITCH IN THE ON POSITION. AFT CABIN EMERGENCY LIGHTS DO ILLUMINATE. CORRECTIVE ACTION: TROUBLESHOT EMERGENCY LIGHTING SYSTEM AND VERIFIED THAT THE CABIN DOOR EXIT LIGHT AND FWD RH WORK SURFACE LIGHT WERE NOT ILLUMINATING. REMOVED #1 EMERGENCY BATTERY FOR TROUBLESHOOTING. PERFORMED EMERGENCY LIGHTING BATTERY PACK CAPACITY TEST IAW CESSNA 680 AMM 33-50-10 AND DETERMINED THAT THE #1 EMERGENCY BATTERY IS INOP. REFER TO SQK 2-2 OF THIS WO# DBZHA FOR REPLACEMENT OF EXISTING #1 EMERGENCY LIGHT BATTERY AND INSTALLATION OF THE CUSTOMER SUPPLIED EMERGENCY LIGHT BATTERY AND FUNCTION CHECK. SEE SQK 3-1 OF THIS WO# DBZHA FOR ADDITIONAL TROUBLESHOOTING PER NETJETS MCC.