What was found
AFTER TAKEOFF, WITH LANDING GEAR SELECTED UP, LT MAIN RED (A) ANNUNCIATOR REMAINED ILLUMINATED WITH LOUD VIBRATION. SELECTED LANDING GEAR DOWN. AIR RETURN. LANDED WITHOUT INCIDENT. CLEANED LT LANDING GEAR DOOR PROXIMITY SWITCHES. LANDING GEAR EXTENSION AND RETRACTION NORMAL. INDICATIONS NORMAL. (K)