As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONTROL CABIN ZONE TEMP LIGHT ILLUMINATED UPON RECALL. GROUNDED - YES. FOUND FLT DECK TRIM VALVE FAULT ON THE TRIM ZONE CONT. RAN BITE TEST REF B737-900 AMM 21-61-00 SYSTEM OP CHECKS GOOD NO DEFECTS NOTED AT THIS TIME AS PRECAUTION CLEANED FLT DECK FILTER SYSTEM OP CHECKS GOOD THIS CLEARS MEL 21-21G.