What was found
NR 2 TANK FORWARD FUEL PUMP LOW PRESSURE LIGHT IS ON WHEN SWITCH IS ON WITH FUEL PRESENT IN THE TANK. CREW ATTEMPTED TO TURN PUMP OFF AND WOULD NOT TURN OFF. LEFT SWITCH IN ON POSITION AND SHORTLY THEREAFTER PUMP LOW PRESSURE LIGHT CAME ON. CREW FOUND PUMP CIRCUIT BREAKER POPPED. *S/D* TROUBLESHOT SYSTEM HAND-OVER-HAND WIRE CHECK IDENTIFIED MODULE 181, RELAY R21 AS CAUSE. REPLACED R21 RELAY. REPLACED P5 MODULE ON FLIGHT DECK AS A PRECAUTION.