As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR SYNOPTIC, TARGET TEMPERATURE INDICATION IS BLANK CREW COMMENTS, AIR COND RESET WILL BRING BACK INDICATION BUT THEN ALWAYS BLANKS AGAIN MAT FAULTED ZONE TRIM MOD VALVE FOR ZONE C MSG. 21-2004 RENDERED ZONE C TRIM MOD VALVE INOP PER MEL 21590.