Never had a problem with my truck until today when it wouldn't start. The first thing I noticed was that there was no electrical power to anything - door locks, headlights, dash lights - nothing. However there was a buzzing sound coming from behind the cab and below the body. I disconnected the battery and the buzzing stopped but resumed when I reconnected the battery. Still the truck won't start, no response at all when I insert and turn the key. The little red dash-top light that no one seems to know what it is was blinking away like it was possessed, but no other indications that the truck was getting any power. With the buzzing sound coming from behind and below the cab, below where the gas filler pipe is, makes me think that the fuel pump modulator or some other related electrical part has shorted out and is preventing power to the rest of the truck.

Update from Apr 8, 2016: Got the thing fixed. As someone else posted, the issue was the "Fuel pump driver module" mounted on the frame below the gas tank behind the cab. They found that it was moderately corroded and wasn't testing properly when checked, often sticking in the 'on' position causing the fuel pump to run constantly even with the engine off. This is what caused my battery to drain over a two day period while not being driven. On replacing the part ($275.08 parts & labor) they let the truck sit overnight to see if it drained and then tested it on the computer the next day and it worked fine. When I lived in Southern California there was no problem because of the dry climate but in Ohio where it rains all thru the year plus with the road salt in winter the part built up corrosion. The service manager said they replace these things a lot but since its not a safety issue Ford won't recall it or cover it past the original warranty.

engine stalls/misses/won't start during rain/heavy humidity

I have had recurring issues with my 2004 F-150 Lariat 5.4L V8. I noticed that the Engine would occasionally miss or stall or completely shut down leaving me stranded. Eventually after several tries I would get it to fire back up but this morning it would not start at all. I was able to correlate each of these instances to times of heavy rainfall and/or humidity. Trouble code at AutoZone called it P1235 "Fuel Pump Driver Circuit Out of Range". I visually inspected the device which is located on the crossmember - severely corroded and open with circuit board exposed. Replaced the part and truck started right up without difficulty. I'm aggravated with the absurdity of this design as my Facebook posting regarding this repair indicates below....

Dear Ford Design Engineers:

Thank you for coming up with the brilliant idea of placing the fuel pump modulator in the undercarriage on the crossmember. In that location it should never be exposed to corrosive environmental conditions (road salt, grime, debris, etc.) In addition, I greatly appreciate the fact that you designed this component as part plastic and part cast, which is in direct contact with the steel crossmember (dissimilar metals) further speeding up the corrosion process as I had nothing better to do this morning than replace this part.....

Signed,

Future Toyota Owner

in the middle of moving, went to start the truck and all it did was turn over. acted like it wasn't getting any gas. checked fuses-there aren't any for the fuel pump. had to get it hauled away, fuel pump failed, had to get it replaced. mechanic says f-150 ,2004s 05s do this around 100,000 mi. ford also designed fuse panel to contain the circuitry for the fuel pump, not a fuse. if the fuel pump over-currents it burns up the panel, not a 50 cent fuse. whole new fuse panel needs replacement, costs $300.00. leave it to engineers, and people wonder Detroit is failing!