As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK LIGHT ILLUMINATED DURING CRUISE. PACK RESET, LIGHT EXTINGUISHED. LIGHT RE- ILLUMINATED, ISOLATION VALVE CLOSED, LEFT PACK SWITCH OFF (QRH). GROUNDED - YES. REMOVED AND REPLACED L/H EXIT SRADA PER B737-900 AMM 21-51-27. OPS CHECKS GOOD. PERFORMED BITE CHECK ON BOTH PACK TEMP CONTROLLERS. NO MORE FAULT LIGHT FOR SRADA EXIT ACTUATOR. OPERATED APU AND PACKS. NO PACK LIGHT. SYSTEM OPERATES NORMAL .