As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF LEFT GEAR DIDN'T INDICATE UP AND LOCKED. RED LEFT GEAR AND GEAR SELECTOR LIGHT ON. GEAR LOWERED NORMALLY. AIR RETURN TO MEM. MAINTENANCE FOUND GEAR PROXIMITY SWITCHES DIRTY. CLEANED AND PERFORMED OPS TEST OF LANDING GEAR. LEFT TRANSITENT LIGHT AND GEAR HANDLE LIGHT EXTINGUISHED.