My fuel pump is not working, why?

I am sorry, but "thinking" you have power to the relays does not do me much good. Let's do it this way.
One of the relays of the four will have the following color wires. My diagram does not tell me which one for sure, but look for these colors. These are the wires going to the relay socket.
1- Yellow-12 volts from the fuse. No power, the fuse is out.
2- Dark green/yellow-power to inertia switch. From inertia switch to fuel tank selection switch, then to fuel pumps.
3- Red-12 volts from computer when key in "start"position. Not "run", start position.
4 Blue/orange-ground from computer with key in "start" position.
Test; jumper wires 1 and 2. You should now have power to the inertia switch, the sector switch and which ever tank is selected, that pump should be running.
If not, check power at fuel pump connection at tank. If you have power there, the pump is bad.

These trucks had a big problem with the switching valve which is located between the tanks on the frame rail on the drivers side.

Please let me know how it goes, we are here to help.

Best, Ken

RACE STREET Could you please use this link https://www.2carpros.com/questions/new
and ask this as a new question, please give all the information you can as well as what you have done to try and repair the issue. Thank you

Does it come on for a few secs when key at run position? If not check the fuel pump relay if it comes on check whether the injectors are pulsing while cranking engine over.

Here is a guide to help you see where you are loosing power

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here is the fuel pump wiring diagrams and engine controls so you can see how the system works.

Check out the diagrams (Below)

Please let us know what you find.

Cheers

IF the front pump is not getting power you got some bad wiring or the switch is bad here is a guide to help you see which with the wiring diagrams below to help you see how the system works. Also these truck needed a new switching valve, I replaced a bunch of these in the shop.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.

Check and test the inertia fuel cut off switch could be tripped or bypass it and see if the pump come On.

This is common the fuel tank pump needs to be replaced. Here is the location so you can get the job done you must get the parts from ford.

This guide will give you an idea of what you are in for with diagrams for your truck below.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

REMOVAL
Raise the rear of the vehicle.
To avoid electrical sparking at the tank, disconnect battery ground cable. Then disconnect the fuel gauge sending unit wire at the fuel tank.
On vehicles with dual tanks, disconnect the ground wire after both tanks have been drained. Siphon the fuel from the tank into a suitable container at the hose between the fuel pump and the fuel tube.
Disconnect the fuel line push-connect fittings at the fuel gauge sending unit.
If the fuel gauge sending unit is to be removed, turn the unit retaining ring counterclockwise and remove the sending unit, retaining ring and gasket.
Loosen the clamp on the fuel filler pipe. Disconnect the filler pipe hose by pulling along the rubber inner tube from the tank filler neck.
If removing the metal-type tank, support the tank and remove the bolts attaching the tank supports to the frame. Carefully lower the tank and disconnect the vent tube(s) from the vapor emission control valve in the top of the tank. Finish removing the filler pipe and filler pipe vent hose if not possible in step 6. Remove the tank from under the vehicle.
If removing the plastic-type tank, support the tank and remove the bolts attaching the combination skid plate and tank support to the frame. Carefully lower the tank and disconnect the vent tube(s) from the vapor emission control valve in the top of the tank. Complete removing the filler pipe if not possible in step 6. Remove the skid plate and tank from under the vehicle. Disassemble the skid plate from the tank.
INSTALLATION
Install new support strap insulation as required.
If installing the plastic-type tank, assemble the skid plate and support straps to the tank.
Raise the tank skid plate and support assembly and attach the vent hose(s) to the vapor emission control valve.
Start the tank neck into the hose.
Position the tank assembly filler against the top straps of the frame. Install the attaching bolts and nuts using thread adhesive. Tighten the attaching bolts and nuts.
NOTE: The plastic tank attaching bolts and nuts do not utilize thread adhesive. Tighten these bolts and nuts.
Insert the rubber inner hose inside the tank filler neck and connect the filler pipe hose. Tighten the clamps.
If the fuel gauge sending unit was removed, ensure all the old gasket material has been removed from the unit mounting surface on the tank. Using a new gasket, position the fuel gauge sending unit to the fuel tank and secure with the retaining ring.
Connect the fuel gauge sending unit electrical connector to the sending unit.
Connect the fuel lines at the fuel gauge sending unit. Install the drain plug, if so equipped.
Connect the vehicle battery ground cable removed in Removal step 2.
Fill the tank and check all connections for leaks.
Lower the vehicle.

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Cheers

Thanks for the heads up it was a pain but I got both pumps done the truck has never worked better. I love this site.

Good morning,

This could be several things. The first thing I would do is check the switch on the dash for power output to the rear tank. I attached a diagram of the switch and circled the wire you need to test for voltage.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Beyond that, I would check for power to the rear fuel pump. If you have power, the pump is bad. If you do not, then you have a wiring issue.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy

This vehicle does not use an external fuel tank switching valve. A supply check valve in the fuel pump assembly opens when the outlet pressure from the energized fuel pump exceeds the opposing check valve spring force.