As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIMARY TRIM FAILED AFTER TAKEOFF. SECONDARY SYSTEM OPERATED NORMALLY. FLIGHT WAS RETURNED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND A PHASE CIRCUIT BREAKER POPPED BEHIND FORWARD FLIGHT ATTENDANT SEAT. RESET CIRCUIT BREAKER, OPERATIONAL CHECK OF PRIMARY TRIM FULL TRAVEL WAS NORMAL. REPLACED PRIMARY TRIM MOTOR AS A PRECAUTION.