As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER SIMULATED EMERGENCY DECENT TO 19K, LT FIRE WARNING LIGHT ILLUMINATED. EMERGENCY CHECKLIST MEMORY ITEMS COMPLETED (ENGINE FIRE-SHUTDOWN). LT FIRE WARNING LIGHT REMAINED ON. CREW DETERMINED THERE WAS NO FIRE (NO SECONDARY INDICATIONS) AND ELECTED TO RETURN TO DEPARTURE. SINGLE ENGINE ILS WAS UNEVENTFUL.