As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT ZONE TEMP LIGHT ILLUNINATED IN AT AT FL340. ACFT GROUNDED. PERFORMED BITE CHECK OF NR 2 PACK/ZONE TEMP CONTROLLER, FAULTED STDBY CONTROLLER FAULT. DUE TO CONTROLLER HISTORY, REPLACED NR 2 PACK/ZONE TEMP CONTROLLER IAW 21-61-20-000-801/400-801, OPS CHECK NORMAL IAW SAME.