What was found
ON TAKEOFF, EN ROUTE, RECEIVED L-2 DOOR WARNING INDICATION, REJECTED TAKEOFF AT LESS THAN 60 KTS. FLIGHT CREW RE-SECURED L-2 DOOR AND WARNING LIGHT EXTINGUISHED, AIRCRAFT DEPARTED TO LAS. UPON ARRIVAL IN LAS MAINTENANCE INSPECTED THE L-2 DOOR PROXIMITY SWITCH AND DOOR OPERATION, NO DEFECTS WERE NOTED. DUE TO RECENT HISTORY OF L-2 DOOR WARNING INDICATIONS A FOLLOW UP WAS WRITTEN TO RE-INSPECT THE PROXIMITY SWITCH AND PERFORM A SOFT LATCH INSPECTION. MAINTENANCE PERFORMED L-2 DOOR RIG CHECK, OPERATION OF DOOR WAS GOOD WITH HANDLE HAVING A POSITIVE OVER CENTER. DISCOVERED JAM NUT ON SENSOR ADJUSTMENT PLATE LOOSE, READJUSTED PROXIMITY SENSOR AND SECURED AND SAFETIED JAM NUT.