As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE START THE CONT CAB ZONE TEMP LIGHT ILLUMINATED DURING MASTER CAUTION RECALL. EXTINGUISHED AFTER PUSHING MASTER CAUTION WHICH WAS ILLUMINATED. GROUNDED-YES. TROUBLESHOT PER B737-800 FIM 21-62 TASK 842. PACK TEMP CONTROL 2 SHOWS FLIGHT DECK TRIM VALVE FAULT. OPERATIONS CHECKED LT AIR CONDITIONING PACK, PER B737-800 AMM 21-00-00. OPERATIONS CHECKED GOOD. AFTER PACK TEMP CONTROL 2 RESET, LT AC PACK OPERATES NORMALLY AND NO FAULTS NOTED.