B Series Truck 4WD L4-2606cc 2.6L SOHC (1992)
Fuel Pump Relay: Description and Operation
Fuel Pump Relay (Circuit Open Relay)
PURPOSE
Supplies power to the electric fuel pump. As a safety feature, the relay is only energized when the engine is running or being cranked by the starter
motor.
LOCATION
Behind driver side kick panel.
OPERATION
The relay has two separate hold in coils, one for starting (cranking) and one for running. During engine cranking, current flows through the start
coil to ground, energizing the relay. The run coil gets power from both the start signal and the ignition switch "IGN" terminal, at relay terminal
"B". Voltage is present at this terminal when the key is in either the "start" or "run" position. The run coil does not energize until the circuit is
completed to ground by the ECU. When the ECU receives a start signal from the ignition switch or a run signal from the ignition coil negative
terminal (tachometer signal), it grounds fuel pump relay terminal "Fc", energizing the relay.
CONSTRUCTION
Relay has separate hold in coils for starting (cranking) and running.
