Fuel Pump Relay
The engine Electronic Control Unit (ECU) provides ground to one side of the coil in the fuel pump relay to control the fuel pump relay. The other side of the fuel pump relay coil is connected to main relay B+, which activates when the ignition switch is "ON". The ECU monitors the control circuit between the fuel pump relay and the ECU. When the ignition switch is turned "ON", the ECU energizes the fuel pump relay, which sends power to the Fuel Pump Control Module (FPCM).