1 Answer

Every Ford Fuel Pump Relay has two basic circuits and for the purpose of our discussion, we'll call them:

A high current circuit and a low current circuit.

Both of these are completely independent from one another, in other words, voltage/current flowing to these circuits do not mix.

The high current circuit is the one that delivers the Voltage to the Fuel Pump in the gas tank (or on the frame rail).

When the Fuel Pump Relay is off  the high current circuit is ‘open’.

In it's ‘open’ state current does not get sent to the Fuel Pump.

The low current circuit is the control circuit that ‘closes’ or ‘opens’ the high current circuit. By ‘closing’ the high current circuit, I specifically mean allowing Voltage to pass to the Relay (internally) and on its way to the Fuel Pump.

Power is applied to circuit 2. This Voltage comes from the EEC Power Relay.

Power is applied to circuit 4. This Voltage comes from the Ignition Switch.

The Fuel Injection Computer then grounds circuit 1.This activates the Fuel Pump Relay to pass current from circuit 4 to circuit 3.Circuit 3is the one that runs to the Fuel Pump (via the Inertia Switch) and delivers the Voltage/Current it needs to activate. Before this Voltage reaches the Fuel Pump, it has to go through the Fuel Pump Inertia Switch first.If the Inertia Switch has been tripped, it will ‘open’ the circuit and the Voltage will not reach the Fuel Pump.

I would FIRST MAKE SURE.the Inertia Switch, located in the trunk or one of the front seat kick pads,  has not been trioed by pressing down on the button.

If you can not do that, take it to a repair shop, WBMS