As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT ZONE TEMP FOR CONTROL CABIN ILLUMINATED. LIGHT EXTINGUISHES WHEN MASTER CAUTION RESET. GROUNDED - YES. ACCOMPLISHED B737-800 FIM 21-62 TASK 801. PREVIOUSLY FLT LEG SHOWED "FLIGHT DECK TRIM VALVE" FAULT CLEARED . NO FURTHER DEFECT NOTED.