As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON GEAR EXTENSION FOR LANDING, THE GEAR DOOR OPEN LIGHT REMAINED ILLUMINATED. COMPLIED WITH ABNORMAL PROCEDURES AND LANDED WITH THE LIGHT ILLUMINATED. REPLACED THE MAIN LANDING GEAR PROXIMITY SWITCH CONTROL BOX IAW DC9 MM. 32-60-03-2-0201.