What was found
ON TAKEOFF, RAISED GEAR AND ALL LIGHTS OUT, BUT AFTER A FEW SECONDS THE LEFT MAIN LIGHT ON FWD PANEL CAME ON. NO LIGHTS ON S/O PANEL. CYCLED THE GEAR AND ALL LIGHTS WENT OUT AND REMAINED OUT. LIGHTS CAME BACK ON BRIEFLY DURING DESCENT AND BACK OUT, SEVERAL TIMES. PERFORMED PROXIMITY BOX BITE CHECK AND ALL OK. CHECKED PROXIMITY SWITCH FOR SECURITY AND OPS WITH HAND HELD TARGET. CHECKED WIRING FOR SECURITY AND BREAKS, CHECKED PER TAFI 32-30-00 AND ALL CHECKS NORMAL.