As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIOR TO COAST OUT WHILE TRIMMING RUDDER NOSE LT, TRIM WAS MOVING VERY SLOW. TRIMMED NOSE RT & TRIM SPEED WAS NORMAL. WHEN ATTEMPTED NOSE LT AGAIN, RUDDER TRIM WOULD NOT WORK, STILL WILL TRIM NOSE RT. MAINTENANCE R&R THE AILERON / RUDDER TRIM CONTROL MODULE. VENDOR SHOP FINDINGS: UNIT FAILED PRELIMINARY FUNCTIONAL TESTING. VERIFIED CUSTOMER REASON FOR UNIT REMOVAL FROM AIRCRAFT. FOUND THE RUDDER TRIM SWITCH DEFECTIVE. REPLACED THE RUDDER TRIM SWITCH.