As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APPROACH INTO DTW, ALL THREE RED UNSAFE LIGHTS REMAINED ON AFTER GEAR EXTENSION. RECYCLED GEAR AND NORMAL INDICATIONS WERE ACHIEVED. AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED LANDING GEAR LEVER WARNING SWITCH S1-89. OPERATIONAL CHECK NORMAL. AIRCRAFT RETURNED TO SERVICE.