As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONT CAB ZONE TEMP ON RECALL. GROUNDED - YES. ACCOMPLISHED PACK TEMP CONTROLLER BITE REF B737-800 FIM 21-62 TASK 801. TEST PASSED BUT THE CONT CAB TRIM AIR MODULATING VALVE WAS MAKING A LOUD WHINING NOISE. BECAUSE OF THE HISTORY AND THE NOISE, CHANGED OUT THE TRIM MODULATING VALVE FOR THE CONT CABIN REF B737-800 AMM 21-61-21-000/400-801. LEAK CHECKED GOOD. ALL GROUND VERIFICATION TESTS SUCCESSFUL.