As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE WHILE TRANSFERRING FUEL, NOTICED THE NR 1 AFT LOW PRESS LIGHT FAILED TO ILLUM WHEN NR 1 FUEL PUMP SWITCH (AFT) WAS PLACED TO OFF POSITION. ALL OTHER PUMP LOW PRESS LIGHTS ILLUM NORMALLY. FUEL FLOW FOR BOTH ENGINES MATCHED AND ONCE BALANCED FUEL LEVELS DECREASED NORMALLY ON BOTH SIDES. GROUNDED - YES. PERFORMED OPS CK OF NR 1 TANK AFT PUMP PRESS SWITCH, PER B737-900 AMM 28-42-11-700/801 & OPS CKS GOOD.