What was found
AFT CAB "ZONE TEMP" ANN ILLUMINATED AFTER PUSHING THE MASTER CAUTION RECALL. EXTINGUISHED WHEN MASTER CAUTION PUSH TO RESET IS PRESSED. GROUNDED - YES. C/W THE FOLLOWING B737-900 FIM 21-62 TASK 847, TASK 801, & TASK 835. VERIFIED FAULT LIGHT ON FOR AFT ZONE TRIM VALVE ON ZONE TEMP CONT #1. VERIFIED 115VAC AT AFT CABIN TAV V145 D3890 PINS 11 & 3. RECONNECTED CONNECTOR TO TRIM AIR VALVE. RETESTED #1 ZONE TEMP CONT BITE - DURING VERIFY TEST GREEN GO LT ILLUMINATED. PUSHED RESET SW & FAULT RESET. BITE TEST OK. ETOPS GROUND VERIFICATION SUCCESSFUL.