What was found
AIR TURNBACK DUE TO AN UNSAFE LIGHT, REMAINED ON AT RIGHT MAIN LANDING GEAR AFTER TAKEOFF. GEAR WAS LOWERED AND 3 GREEN LIGHTS WERE NORMAL. FOUND BROKEN PIN LOCK AT DISCONNECT D4536, PIN NR 3, WIRE 424-A-R. REMOVED AND REPLACED PIN PER MM GEAR RETRACTION GOOD.