As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON LOWERING LANDING GEAR ON APPROACH, THE LEFT MAIN LANDING GEAR GREEN DOWN AND LOCKED INDICATION LIGHT WOULD NOT ILLUMINATE. CREW COMPLIED WITH ABNORMAL CHECKIST. MAINTENANCE INSPECTED AND REPLACED THE LEFT MAIN LANDING GEAR DOWN LOCK SWITCH. OPS CHECKS WERE SATISFACTORY IAW DC-9 MM 32-60-01.