What was found
(CAN) AFTER TAKEOFF, LEFT MAIN GEAR UNSAFE (RED) LIGHT STAYED ON AND STARTED FLASHING. GEAR HANDLE UN SAFE LIGHT ILLUMINATED THE SAME AS THE GEAR HANDLE ANNUNCIATOR LIGHT. MAINTENANCE: REMOVED LEFT MLG PROXIMITY SENSORS IAW DASH 8 400 AMM 32-61-06-000-802. INSTALLED NEW FROM STOCK LEFT MLG BOTH PROXIMITY SENSORS IAW Q400 AMM TASK 32-61-06-400-802 PARA 1-4A STEPS (1)J AND (8) THRU (16). STEPS (2) THRU (7) NOT REQUIRED HARNESS ALREADY MADE UP PARA 5 A.B.C., PARA D NOT REQUIRED ONLY DOWN LOCKS REPLACED.