As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK 'OFF' LIGHT WILL NOT EXTINGUISH WITH PACK OPERATING. TAPPING ON POSITION SWITCH OF FCV EXTINGUISHES LIGHT. INTERMITTENT NEEDS NEW FCV 643-9118. REPLACED FCV; REF MM 21-51-01, THROUGH STEP E 6D, PREP FOR POST INST TEST. FURTHER TEST REQUIRES APU RUNNING. RAN APU AND ENGINES AND FOUND PACK AND LIGHTS TO OPERATE CORRECTLY.