Fuel Pump Relay: Description and Operation
CIRCUIT OPERATIONWhen the ignition switch is in either the START or RUN positions, it connects circuit A1 from fuse 2 in the Power Distribution Center (PDC) to circuit A21. Circuit A21 splices to circuit F12 and supplies battery voltage to the coil side of the fuel pump relay. The Powertrain Control Module (PCM) provides ground for the relay on circuit K31. Circuit K31 connects to cavity C19 of the PCM.
When the PCM grounds the fuel pump relay, contacts inside the relay close and connect circuit A61 from fuse 21 in the PDC to circuit A141. Circuit A141 supplies voltage to the fuel pump motor (part of the in-tank fuel pump module).