What was found
THE CREW REPORTED THAT THE CABIN TEMPERATURE WAS EXTREMELY HOT AND WAS DIFFICULT TO REGULATE WITH CABIN CONTROLS IN BOTH MANUAL AND AUTOMATIC MODE SETTINGS. THE SYSTEM WAS EMITTING A BURNT RUBBER SMELL INTO THE COCKPIT AND CABIN AREAS. WHEN THE COCKPIT TEMPERATURE WAS ADJUSTED IT APPEARED TO CHANGE THE CABIN TEMPERATURE. AFTER THE ENGINE ANTI-ICE WAS SELECTED ON, THE BURNT RUBBER SMELL SEEMED TO GET WORSE. MAINTENANCE REPLACED THE COCKPIT TEMPERATURE CONTROL VALVE ASSEMBLY AND PERFORMED A COMPLETE OPERATIONAL TEST OF THE AIR CYCLE MACHINE. TEST PORT PRESSURES AND ACM TEMPERATURES WERE ALL WITHIN LIMITATIONS. OPERATIONAL AND LEAK CHECKS WERE GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.