Found my culprit to be fuse#21. Cluster keep alive power. But as to which component on that circuit is causing it is still a mystery since the radio, dome light, power windows and dash cluster are all powered from this.
What I am wondering next, is could a sending unit be bad to one of the guages and be pulling power while its off or is there a short in a wire or a corroded connection some where. Ahh the joys of owning a Ford.
I also found my culprit, but Ford is not to blame. It was an aftermarket trailer brake controller that was causing my drain. Hopkins 47235 Brake Control Impulse. Now, I can't conclude yet that this was it, all I can conclude is that with this unplugged my current draw decreased according to my ammeter and with this unplugged the problem has been gone for a week.
Alright I've been having this problem also for awhile now also and just started to troubleshoot my problem. The batteries are good and hold their charge just fine but after leaving them hooked up to the truck they will drop from 12.7v to just below 12.5v in one night. Nothing is left on as far as I can see. I was doing the parasitic draw test today on the drives side battery after letting the truck sit for an hour to make sure everything would go to sleep (aux side was still hooked up at this time) was reading 0.15 which is higher then it should be from what I have been reading online. While I was still connected I had someone pull the neg off the aux battery and the reading dropped down to 0.08? We put it back on and off a couple of times to verify and it would go back up to 0.15 then back to 0.08. I'm not to sure whats going on there? I then decided to leave the drivers side hooked up and took a reading on just the aux and it was reading less draw then the drivers side had. Not really to sure whats going on there? I was also reading somewhere someone mentioned that if the key-less entry fob had a dying battery in it that could cause the relay to stick open and draw power when you use it. So I tried locking the doors and waited a couple mins and it was drawing 0.22 and wouldnt drop down but I only waited 5 mins and need to wait longer next time.
1. Radioshack sells a pretty cheap DC ammeter of "clamp on" type. It's about $65 and works best when clamped over the two cables leaving the negative post of the battery. This is handy to have because it's time consuming to put an ammeter in line.
2. It takes a FULL 30 minutes for everything to shut down after locking the truck with the key fob.
3. When you hit "lock" on the key fob, the amperage starts at around 6 amps, drops pretty quickly to around 1 amp when the interior lights and other stuff turns off, then drops to something less than .5A, then in 30 minutes drops to the "hundreds of milliamps" range -- perhaps 400 milliamps or .04 amps.
4. The radio shack tester is not very accurate at these low levels -- the instructions say "8 digits of variation" so when it reads .08 that could be anything from 0 amps to .16 amps. Still it was accurate enough for my wife to see a SIGNIFICANT drop from .5A to .2A when I pulled the brake controller.
5. The tester needs to be zeroed each time the current changes a lot. Sometimes it will keep reading 6 amps and when I take it off, zero it, and return it, it ready .5 amps.
6. In theory you can find the circuit easily by hooking this meter up as described above, having someone read it while you pull fuses one at a time. However, since it takes 30 minutes to shut down and you reactivate things by opening a door, I suggest rolling down a window and climbing in after 30 minutes. Also, this did NOT find anything when I did it twice. I only found the drain when I unplugged my brake controller -- surely that is powered by some circuit, so I don't know why I did not find it when I pulled a fuse.
My 2002 f350 powerstroke started killing batteries. I figured out that the stereo is turning on all on its own while the truck is parked. I have a kenwood CD/gps unit and a huge memphis amp and subs- figured it out when the bass was shaking the house at 0200AM
Now if I manually turn my radio off or set it on standby, my batteries are fine. It died the other night after going several months. I got in it at work last night and the DVD display was on-but since it was on "standby" the amp was off and nothing drained the battery.
SO- is it
a relay under the dash? it seems to happen when it rains-maybe water kicking a relay on?
At least I know its the sound system now-NOW I need to figure out if its the ignition switch or something else.
Before anyone says it-I had this problem with the factory radio so it is not my kenwood. Also I replace my CD players every couple years due to technology and this has happened with both the stock and aftermarket radios.
I have the same exact issue-but it has to be raining. I didnt drive my f-350 for a bout a week. Went out yesterday and saw the radio was on (I had been turning it off- left it on but in standby so it wasnt powering amps or playing. Today went to start it and they were dead. So my radio mysteriously comes on- usually when it rains- is it a relay or the ignition switch? Someone has to have seen this. I have had this problem since the truck was new it was originally blamed on the underhood light switch
I have 2004 F150 FX4. Replaced 3 new batteries.. found out it was the radio causing electrical issues. disconnected radio... also replaced Computer Modual.. (Expensive) but no issues with battery since.
I had a similar problem with my 2007 supercrew lariat. Advance auto checked it. Bad battery. after a new battery, one month later, same problem. Battery would go dead after sitting for a day or two. This went on for a month till I had time to get back in and recheck the battery. The battery was no good but this time they also said I had a parasitic draw on the system. They replaced the battery. I traced the draw back to the xm radio equipment in the dash..Disconnected it and no more problems.
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