What was found
(CAN) FLIGHT CREW REPORTED RECEIVING A MIS-TRIM MESSAGE ON THE ID-802. THE AUTO-PILOT WAS THEN DISENGAGED & FLT CREW ATTEMPTED TO MOVE TRIM MANUALLY TO A NOSE DOWN ATTITUDE. A RESTRICTION TO THIS MOVEMENT WAS FELT IN THE TRIM CONTROL. AN EXTENDED ROUTE WAS REQUESTED FROM ATC & THE AIRCRAFT LANDED WITHOUT INCIDENT. IT WAS NOTED THAT THE ELEVATOR MANUAL TRIM APPEARED TO OPERATE NORMALLY AFT OF THE RESTRICTION. (DETAIL: INCIDENT OCCURRED DESCENDING THROUGH 150, VMC, +5C REF: ASR44R/00/DH8ENGINEERS: COULD NOT REPRODUCE FAULT, BUT ON FURTHER INVESTIGATION TRIM CABLE TENSION DISCOVERED TO BE 0 LBS ONLY, CABLES THOROUGHLY INSPECTED, RE-TENSIONED. FUNCTIONALLY CHECKED & A/C RETURNED TO SERVICE.