As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR COND CONT CABIN ZONE TEMPERATURE LIGHT ON RECALL AFTER START. GROUNDED-YES. BITE CHECKED BOTH ZTC'S, REF B737-800 FIM 21-62 TASK 801. NR 1, NO FAULTS. NR 2 FAULTS CONT CABIN TRIM VALVE. PERFORMED B737-800 FIM 21-62 TASK 832, FAULT RESETS. RAN VERIFY TEST NUMEROUS TIMES W/NO DEFECTS. ETOPS GROUND VERIFICATION TEST PASS.