As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED AFTER DEPARTURE, PRIMARY PITCH TRIM CONTINUED TO RUN AFTER COPILOT RELEASED THE SWITCH. EXECUTED PITCH TRIM MALFUNCTION EMERGENCY CHECKLIST AND RETURNED TO DEPARTURE AND LANDED. MAINTENANCE WAS ABLE TO DUPLICATE THE PITCH TRIM PROBLEM. REPLACED COPILOTS CONTROL WHEEL TRIM SWITCH AND ALL OPERATIONAL CHECKS NORMAL.