As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) FAULTY PILOT TRIM SWITCH CAUSED VERTICAL VOLTAGE BLEEDING WHICH PREVENTED PROPER HORIZONTAL STAB TRIMMING WITH AUTOPILOT ENGAGED. THE SET SCREW HOLDING THE SWITCH IN PLACE HAD BROKEN THROUGH THE SIDE OF THE SWITCH ALLOWING THE BROKEN PIECES INSIDE THE SWITCH WHICH OVERTIME CAUSED THE MALFUNCTION OF THE SWITCH.