What was found
ZONE TEMP -CONT CAB ILLUMINATED ON MASTER CAUTION RECALL, ASSOCIATED ZONE TEMP-LIGHT EXTINGUISHED UPON MASTER CAUTION RESET. GROUNDED - YES. PERFORMED B737-900 FIM 21-62 TASK 842, PZTC 2 BITE SHOWS FLT DECK TRIM VALVE FAULT ON PREVIOUS FLT LEG, NO FAULTS ON VERIFY. REMOVED CONT CAB DUCT OVERHEAT SWITCH S931 FOR TROUBLESHOOTING, FOUND DAMAGED. REPLACED REF B737-900 AMM 21-61-05/401. OPS CHECK GOOD REF AMM 21-61-00-700-811-002. REPAIR CONFIRMATION SUCCESSFUL, ZONE TEMP LIGHT DOES NOT ILLUMINATE. RAN BOTH PACKS AT VARYING TEMPS FOR 5 MINUTES, NO FAULTS FOUND. ETOPS GROUND VERIFICATION SUCCESSFUL.