As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT WHILE MANUALLY DRIVING THE RUDDER TRIM WITH THE RUDDER TRIM SWITCH, THE RUDDER TRIM "RAN AWAY" FULL RT. PILOT COULD DRIVE IT BACK TO THE LT WITH THE TRIM SWITCH, BUT WHEN HE TRIED ADDING RT RUDDER TRIM IT WOULD KEEP DRIVING TO FULL DEFLECTION RT. WORKED FINE IN CRUISE. MAINTENANCE REPAIRED BY REPLACING FAULTY TRIM ADAPTER RELAY BOX, PN 065-00195-0100, SN KT2810-1712.