What was found
AIR TURN BACK ON CLIMB OUT, EXPERIENCED RUDDER AND TRIM PROBLEMS. UNABLE TO TRIM THE RUDDER, WITH AN INDICATION OF ONLY 2 UNITS, LEFT TRIM WILL NOT MOVE. REQUIRED AILERON 20 UNITS TO THE RIGHT IN ORDER TO MAINTAIN STRAIGHT AND LEVEL FLIGHT. TURNED BACK TO AIRPORT AND LANDED WITHOUT FURTHER EVENT. MAINTENANCE REMOVED AND REPLACED THE RUDDER TRIM CONTROL SWITCH, OPERATIONAL CHECK WAS GOOD. SDR WILL BE SUBMITTED UPON RECEIPT OF VENDOR BENCH TEST REPORT.