As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LANDING GEAR DOOR OPEN LIGHT REMAINED ON AFTER GEAR RETRACTION. FLIGHT RETURNED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND GEAR DOOR OPEN LIGHT SOCKET L2-265 MALFUNCTIONING (REMAINS IN PRESS-TO-TEST MODE). REPLACED SOCKET, OPERATIONAL CHECK NORMAL.