What was found
WHILE ON APU CONTROL CABIN TEMP RAN AWAY TO 60 C AND WOULD NOT RESPOND TO TEMP SELECTOR, THEN PACK TRIP ILLUMINATED WAITED FOR A FEW MINUTES AND DID A PACK RESET. TEMPERATURE BEGAN TO RUN FULL HOT WITH TEMP SELECTOR IN FULL COLD. GROUNDED - YES. REF TSR 701460 FOUND SENSE LINE ON LH ACM FOR THE STBY TEMP CONTROL VALVE LOOSE. REMOVED LH ACM PER B737-900 AMM 21-51-04. FOUND THE FAN IMPELLER DAMAGED AND ACM SEIZED. NO FOD DAMAGE NOTED IN THE COOLING AIR EXHAUST PATH. VISUALLY INSPECTED THE HEAT EXCHANGERS. NO DEFECTS. INSTALLED NEW LH ACM PER AMM 21-51-04-400-802-002. ACM INSTALLATION TEST PASSED. LEAK AND OPS CHECKED GOOD.