As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER EXPERIENCING MOD MOUNTAIN WAVE TURBULENCE AT FL330, GOT LEFT GEAR RED AND GREEN LIGHTS WITH GEAR HANDLE IN OFF OR UP POSITION. UPON GEAR DOWN SELECTION RED AND GREEN LIGHTS REMAINED ON. VISUALLY INSPECTED THE GEAR WERE DOWN. LANDED AND PINNED GEAR. REPLACED LANDING GEAR ACCESSORY UNIT.