What Happens When the Fuel Pump Relay Fails?

[McPresley]

Fuel pump relay failure symptoms: starter does not rotate; starter cranks weakly; starter spins freely. The relay serves both as a control switch and the controlled component (actuator). The fuel pump relay acts as the control switch for the fuel pump, but its coil can only complete the circuit through the ECU's ground point when the driving transistor in the ECU is activated. Possible causes of starter failure to rotate include: 1. Power supply issues - severely depleted battery, sulfated or short-circuited plates, poor contact between battery terminals and cable clamps, loose connections in starting circuit wiring. 2. Starter malfunctions - poor contact between commutator and brushes, open or short circuits in field windings or armature windings, grounded insulation brushes, open/short/grounded solenoid switch coils or burnt contacts. 3. Starting relay faults - open/short/grounded relay coils or poor contact at relay points. 4. Ignition switch problems - loose wiring or internal contact failure. 5. Starting circuit wiring faults - open circuits, poor wire connections or disconnections in starting circuits.