As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE START #1 "PACK" OVHD LIGHT ILLUMINATED / "AIR COND" MC. GROUNDED - YES. #1 CONTROLLER FAULTS THE TEMPERATURE CONTROL VALVE. THE FAULT WILL NOT RESET ON BOX AFTER RUNNING VERIFY. IN THE COCKPIT THE PACK LIGHT DOES GO OUT AFTER RESETTING THE SIX PACK. PERFORMED BITE TEST OF L/H PACK ZONE CONTROLLER, NO CURRENT FAULTS RECORDED, REF B737-800 AMM TASK 21-61-00. REMOVED AND REPLACED L/H TEMPERATURE CONTROL VALVE. OPS TEST GOOD. REF AMM 21-51-10.