As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT DURING APPROACH TO LANDING THAT PRIMARY PITCH TRIM FAILED & THE CREW WAS REQUIRED TO SWITCH TO SECONDARY TRIM. TROUBLESHOOTING FOUND THE HORIZONTAL STABILIZER TRIM CONTROL BOX DEFECTIVE. THE UNIT WAS REPLACED WITH A REPAIRED UNIT. FUNCTIONAL CHECKS WERE SATISFACTORY.