As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, AUTO PILOT TURNED ON BY ITS SELF. RETURNED TO FIELD. WHILE ON THE GROUND THE AUTO PILOT TURNED ON BY ITS SELF. RAN THE TRIM WHEEL FULL NOSE DOWN AFTER DISCONNECTING AND TRANSFERRING TO FIRST OFFICERS SIDE IT AGAIN TURNED ITSELF ON. REPLACED AUTO PILOT PANEL. OPS CHECKS GOOD. S/N ON: 1689, S/N OFF: 2176.