EmilyFo

Hello,
I have a 2004 F150 4x4 that had about 115k on it. It has the 5.4 Triton engine. 3 months ago it just died driving down the road. We had a tow truck tow it to our local repair shop and they fixed the fuel pump. From then on the battery wont stay charged. When we turn the key off it sounds like the fuel pump is still running between the cab and box. We took it back to the repair shop and they assured us it was fine and insisted that it wouldnt drain the battery for them. The issue continued so we took it to the ford dealership that we purchased it from. They also insisted that it was fine after a month of them having it. Obviously the issue is still there and it is still draining the battery. So far we have replaced the starter, battery, and fuel pump in attempts to fix it. We took it to yet another repair shop who at least admitted that there was something not right but after a month of having it gave up saying they couldn't figure it out. We are truly running out of options. If anyone could help us out at all it would be greatly appreciated.

Edit: We disconnected every fuse one at a time to determine if that will make the noise between the box and cab shut off. The noise continued even after the key was out and we disconnected all of the fuses.

Martian

Can you pinpoint where exactly you hear the noise? You said pump is running "between the cab and box". The fuel pump is inside the gas tank. See if you can find (as close as you can) the sound and try and describe it better or even just take a picture of the general area where you hear it.

EmilyFo

The noise is like humming or the sound of a small electric engine. It is loudest when you stand by the rear drivers side door, and it seems to come from between the box and cab.

Martian

Sounds like a stuck lock or window motor. Pop off the door's arm rest with a flathead screw driver to access the switch panel for the door locks and windows. Pull the switch box out and unplug it. See if the sound goes away.

EmilyFo

Just ran out and tried it, humming/clicking continued after I unplugged it. I'm not sure if it matters but the humming noise does go away eventually but will start again if you try to start the truck and its dead. It will stop after 20-25 minutes. It will also stop if you connect the battery to a jump box.

ColdinCanada

electronics is tricky but taking a logical approach is key.
What we know:

You have a parasitic drain on your battery and you hear an audible noise with no key in the ignition. This is really a blessing because most of the time there is no audible cue.

Going forward, when you hear this have someone else help you. Listen to the sound and have them turn the key to ON without starting. Does the sound change? IE you hear the actual fuel pump prime up?
Also pull fuses for electrical components one by one and listen for the noise to stop. Start with Windows first. Make sure if you have the electric rear window option you find that fuse too.
Report back!

lewissa81

There's a possibility the battery could be shot. Quite a few people have reported that when their battery was weak or at the end of its life, they would hear a humming and/or clicking from the rear firewall. I forget the name of the part, but there's a little ecu that control body electronics mounted there.
Have the battery tested, or just replace if it's old.

techrep

iTrader: (1)

I guess you missed the part about the new battery...

Rick's 06

Sounds like you must have a parasitic draw on your battery if you hear something humming. However I'd do a parasitic draw test on your system just to verify. I'm baffled that neither of the the mechanics that worked on your truck have done this simple test. Once you verify you have a parasitic draw, then start pulling fuses to see which circuit it's on. It has to be on one of them.

To perform the check, remove your negative cable from the battery terminal. Place your meter on amps and probe both the negative cable and terminal at the same time while they're separated. A normal reading is around 5mA. If you've got something running you should see a much higher reading. Now Keep your meter connected just like you have it and start pulling fuses one at a a time. You'll need a helper to read the meter while you do this, or get some jumper wires to allow you to take the meter with you inside the truck when you pull those fuses. Post back with your findings.

Martian

People keep saying to pull fuses, but she said she did that already...

Agreed with Rick's though. Do it again with the help of a meter, don't just eyeball or earball it.