What was found
CABIN PACK HOT CAUTION LIGHT ILLUMINATED DURING CRUISE AT 15,000. PER E/A CHECKLIST, TURNED OFF CABIN PACK. CAUTION LIGHT STILL ILLUMINATED AT PARKING. APPROXIMATELY 10 - 15 MINUTES AFTER THAT CHECKLIST CABIN PRESSURE MASTER WARNING ILLUMINATED. STARTED E/A CHECKLIST BUT QUICKLY DESCENDED THROUGH 9,000 FT. DURING APPROACH, THE LIGHT EXTINGUISHED. AIRCRAFT REMAINED UNPRESSURIZED TO TOUCHDOWN. REMOVED FROM SERVICE. CDS SHOWS FAULTS 7105, 7106, AND 7107. R & R THE CABIN COMPRESSOR OUTLET TEMP SENSOR IAW AMM 21-51-91-000-801/400-801. OPS TESTED THE ECS TEMP CONTROL IAW AMM 21-61-00-710-803. OPS TESTED GOOD FOR FLIGHT DECK CONTROL. NO CABIN PACK HOT CAUTION. AIRCRAFT RETURNED TO SERVICE.