What was found
ONE HOUR INTO CRUISE AT FL410, DETECTED AN UNDEFINED ODOR. TEMP SELECTOR WAS IN 11:00 POSITION. THE LT SIDE OF THE CABIN WAS NOTICEABLY WARMER THAN THE RT SIDE. LATER, WITH TEMP SELECT AT 4:00 POSITION THERE WAS NO DECREASE IN ODOR AND NO CHANGE IN TEMPERATURE. THE RT SIDE OF THE CABIN DID HEAT ON DESCENT. VERY LITTLE AIR FLOW CAME OUT OF DEFOG VENTS IN COCKPIT. FOUND RAM AIR DUCT DISCONNECTED IN AFT BAY. SECURED DUCT. CLEANED COALESCER SOCK IAW AMM 221-70-00. PERFORMED ENVIRONMENTAL SYSTEM FUNCTIONAL TEST IAW AMM 21-00-00. OPS CHECKED GOOD AT THIS TIME. NO ODOR NOTED.