As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONT CAB ZONE TEMP LIGHT ILLUMINATED AFTER START. GROUNDED - YES. CONFIRMED CONT CAB ZONE TEMP LIGHT IS ON. PERFORMED B737-800 FIM 21-62 TASK 839. FOUND LIGHT ILLUMINATED ON TEMP CONTROLLER 2, FOR FLIGHT DECK TRIM VALVE. RESET AFTER VERIFY TEST. CONTINUED TO FIM 21-62 TASK 832. GOOD VOLTAGE AT CONNECTOR 03886. PER FIM REQUIRES REPLACEMENT OF " CONTROL CABIN TAV, V142." LOCATED IN LEFT ECS BAY. REMOVED & REPLACED LH TEMP CONTROL VALVE REF B737-800 AMM 21-51-10-400-801. OPS CHECK GOOD.