I've been trying to troubleshoot a battery drain issue on my wife's 05 F150 for several days now and have read through many posts trying suggestions from each.

I've come to a point that I'm not sure what to tackle next. I've hooked up a voltmeter in series to read the amp draw on the battery, it is shows a load of about 4.8 to 4.9 amps constant with nothing on after sitting overnight with the battery completely disconnected. I've now had someone watch the meter while I took each relay and fuse out of the fuse box both under the hood and inside the cab. None of these changed the draw on the battery, I also tried disconnecting the alternator completely and still no change.

I'm pulling my hair out on this one, as you can imagine my wife is not pleased either that her pickup is out of commission.

Does anyone have any other suggestions on what to try.

Thanks in advance, jody.

 

Did these models have problems with the entire fuse box housing? Seems I read somewhere that some people had to replace the entire housing, can't remember the reasons...

If you have pulled all fuses and relays, it seems the problem would have to be between the battery and the fuse box housing and relay housing. One would assume you would need to trace the power wire's leading to said places along with tracing the ground to the frame. Not sure if a corrosive ground to the frame would cause that large of a power draw. Did you have all the fuse's and relays removed at one time just to make sure your pair of eyes didn't miss it? Good luck

 

There should be a direct connection to the starter as well from the battery. With the information available, my money is on the starter solenoid. You might be able to use a infrared camera and look for a hot spot. Something drawing ~5 amps should have a little heat build up...

 

The fuses were done one at a time, with some done a couple of times just to confirm.

On the starter recommendation, I forgot to mention that I unhooked the two leads off the positive terminal, one that goes to back behind the battery, the other goes to the alternator, when i remove those i still have the lead going to the starter in place and the draw on the battery drops to 0.

I was worried that my only option would be the short between the fuse panel and the battery.