As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ELECTRICAL TRIM FAILURE IN FLIGHT RESULTING IN A FULL RT DEFLECTION ON THE TRIM ACTUATOR. PRECAUTIONARY LANDING CONDUCTED AT AIRPORT OF ORIGIN. ACFT TOWED TO MX FACILITY. INSPECTION REVEALED THAT THE TRIM SWITCH LOCATED ON THE CYCLIC HAD BECOME STUCK IN THE FULL RT POSITION RESULTING IN TRIM MOTOR ACTIVATION TO FULL RIGHT. REPLACED TRIM SWITCH WITH SERVICEABLE PART.