What was found
AFTER T/O NR 6 LED FAILED TO RETRACT. COMPLIED WITH QRH AND RETURNED TO MEM. REPEAT WRITEUP, NO DIRECTIONAL PROBLEMS. DURING CREW DEBRIEF, INDICATION WAS FOR NR 6 LEADING EDGE SLAT, NOT KRUEGER FLAP. AFTER TRANSLOAD, CYCLED FLAPS SEVERALTIMES AND FINALLY DUPLICATED PROBLEM WITH NR 6 SLAT AMBER {INTRANSIT} LIGHT ON BOTH FWD AND AFT PANELS. LEFT FLAPS EXTENDED FOR MORE T/S REF 727 MM 27-82-001-4. DURING T/S OPERATED L/E FLAPS AND SLATS APPROX 30 CYCLES. THE NR 6 FLAP IS THE ONLY LED THAT FAILED INDICATION, ABOUT 8 TIMES OUT OF TEN IT FAILED. AT NO TIME DID THE NR 6 SLAT FAIL INDICATION. INSTALLED FLAP POSITION SWITCH PER BOEING MM 27-82-0001-4. SYSTEM OPS CK OK.