As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING THE PRE-FLIGHT CHECKS, THE RUDDER TRIM SWITCH WOULD NOT SPRING RETURN TO CENTRE WHEN RELEASED. THE RUDDER TRIM WOULD CONTINUE MOVING UNTIL THE SWITCH WAS MANUALLY POSITIONED TO NEUTRAL. MAINTENANCE DETERMINED THAT THE RUDDER TRIM ROTARY SWITCH SPRING HAD FAILED. THE AILERON/RUDDER TRIM PANEL WAS REPLACED AND THE AIRCRAFT WAS SUBSEQUENTLY RELEASED TO SERVICE.