As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON APPROACH INTO DTW UPON GEAR EXTENSION, GREEN SAFE OR RED UNSAFE LIGHTS DID NOT ILLUMINATE. RECYCLED GEAR ONE TIME. FOLLOWED COCKPIT OPERATION MANUAL PROCEDURE AND ALL GREEN LIGHTS ILLUMINATED. FLIGHT LANDED WITHOUT INCIDENT. INSPECTED UP AND DOWNLOCK SWITCHES AND REPLACED RELAY R2-28. GEAR OPERATION CHECKED OK.