What was found
ON DEPARTURE FROM SFO, LANDING GEAR WOULD NOT RETRACT. ALL GREEN REMAINED ILLUMINATED & ALL REDS EXCEPT RIGHT A WERE ILLUMINATED W/GEAR HANDLE IN UP POSITION. CYCLED GEAR - SAME RESULTS. RETURNED TO SFO. PERFORMED GEAR SWING. OPS CHECKED GOOD BUT NOTICED RIGHT MAIN RED -A- LIGHT FLICKERS. SWAPPED RT MAIN UPLOCK A & B CONNECTORS PER SNL 120-32-0015 AND DEFERRED RED -B- SYS. SWAPPED HARNESSES BACK TO ORIGINAL POSITION, RIGHT UPLOCK AND REPLACED -A- HARNESS WITH A SERVICEABLE UNIT. SWUNG GEAR SEVERAL TIMES. OPS CHECK GOOD.