I have a 2004 F150 5.4L. The other day without warning the truck had a lot of trouble starting. I was able to get it going by leaving the key in the ON position and waiting about ten seconds to let the fuel line prime and it would eventually start. I suspected maybe the fuel filter was clogged so I changed it out. The same problem remained so I started listening to the fuel pump, it wasn't always coming on when the key was turned to the ON position. Now the fuel pump will not turn on at all. I changed the fuel pump module which didn't fix the problem. Then I dropped the gas tank and tested the fuel pump which works fine when its hardwired to a 12v battery. For some reason I'm not getting any power to the fuel pump. Searched the manual and internet all over for a relay or fuse but I can't find anything. Does anyone have any ideas?

 

Are you referring to the fuel pump driver module? This is becoming a high failure item from corrosion due to its location and mounting method.

There should be a fuel pump relay, look in the manual a little closer.

 

Ya I was referring to the driver module located above the spare tire. Changed it out but the old one looked in good condition, very little corrosion and no cracks. I've also tried pressing the fuel pump reset button with no results. Thinking it's a relay or some other electrical issue but still can't find a fuel pump relay or fuse anywhere in the manual or online.

 

I just downloaded your manual - and you are correct. Strange - my 03 manual says mine is relay #301 in the PDB under the hood.

 

I guess I'll just try and go through the wiring today and see if I can find any issues.

 

Bought a Hayne's repair manual for the truck and it showed me a relay that is soldered directly onto the fuse circuit board. The owners manual for the truck has no mention of this relay. Tapped it lightly with the handle of a screwdriver and its been working ever since.

 

This relay is soldered into the fuse circuit board on the passenger side kick panel correct?

Exactly the post I've been searching for. Thanks GLC and Thank You jce for following up with your solution. I'll give this a shot tonight and see if it helps my hard start issues I've had lately.