2008 F 150 dead battery/battery draw

[jwmiller33]

so for the past couple months, i have been driving my step dads 2008 f 150 king ranch edition. it has a lot of miles on it (past warranty), but thats cuz my step dad drove from central iowa to northern MN a bunch of times over the last year, so the truck is still in really good condition.

anyways, about 2 months ago when it started getting cold, i went to start the truck one night after class and it wouldnt turn over. so i got a jump and drove it home and it did it a couple more times within the next couple days, so i took it in to a place to have them look at it. they told me there was something that was drawing power from the battery and not turning off when the truck was turned off, and they were going to have to pull fuse by fuse to find out which one it is. $250 later, they tell me it was the heated seats that werent turning off and causing the battery to die. so about a week later after they pull the heated seats fuse, it does it again. over the past month when it has been really cold, the problem has been happening more and more frequently. i have a jump pack in the back of the truck, so its not THAT big of a deal when i have to jump it, but it sure is a pain in the pink flamingos when i have to keep doing it everyday, especially in this cold weather.

does anybody else have this problem with their f 150? or has anybody heard of this problem happening to f 150s? this truck is only a year old, so it should be able to START in the winter. i could go get a beater car for $500 that would start more frequently then this one year old truck. i know i obviously need to bring it in again to find out what else is drawing power from the battery, but i was hoping someone on here might have heard of this problem before and could help me out. i dont know hardly anything about cars/trucks besides how to change oil and a tire.

thanks for the help!

[pinkfloyd4ever]

So I get the whole heated seats part, to me if the battery has been drained down repeatedly and needing jumps, maybe its time for a new battery? But also back to the place that diagnosed the whole heated seats and tell them to start over, on their dime too

[pinkfloyd4ever]

also do other search for TSBs for an 08 F150 maybe there is something about it.

And give yourself some cred, didn't you flip an old lund boat and make it look like it just came off the showroom floor?

[croixflats]

That a good start changing the battery. Do that before the battery dies and wont let you jump start it.

I got a bad battery from Fleet farm year before last and last winter when the camery would sit more than 2 days battery would be dead. I read in the owners manual if you leave the lights on and shut the car off and pull the keeys there still is a draw on the battery, on the camery you pull the keeys and open the door the lights go off even when the light switch is on. Replaced the battery and no longer have issues. Dont know if the Ford shuts the lights off after pulling keeys or not but if they do the power seats may have weakened the battery to the point where the headlight draw causes the problem now.

[fishinben351]

i have a harley davidson edition with heated seats mine started right up in the 14 below. ive never had a problem starting it up in the cold, i have a newer battery i only replaced it because it was 10 years old and you never know when it will decide to die. ive had chevys in the past and this is by far the most reliable truck!

[fishinben351]

if i had to guess its just a bad battery

[jwmiller33]

thanks for the input guys... one of my first thoughts when it initially happened was maybe the battery died and needed to be replaced. but when we took it in to that place, they tested the battery and said it held a charge, but there was just something that didn't shut off when the car was turned off that continued to draw power from the battery and eventually made it so low voltage it wouldnt start. i figured that since this truck was only ONE YEAR OLD, the battery should be fine at least for a couple more years, unless i got a lemon. they also said the alternator was fine, as well as the battery. so they ran their tests and pulled one fuse at a time to see what was drawing the power, and it was the heated seats module.

fishinben- its not that the heated seats stay on when its cold out. they arent even turned on at all. it's just the heated seats module continues to have a draw on the battery when its turned off, but this is only sometimes, which makes it even harder to diagnose.

And give yourself some cred, didn't you flip an old lund boat and make it look like it just came off the showroom floor?

yes, i did redo that old lund and made it look respectable. how did you remember that was me? that was almost a year ago now that i posted that thread

[jwmiller33]

anyone have any suggestions besides getting a new battery?

[pinkfloyd4ever]

Re: boat, I followed your posts some, gave me ideas when I re-did mine.

Re: truck, I am looking to upgrade from my 92 chevy truck, so i have been doing internet research. I would think even putting a simple search engine search for a 2008 F150 should turn up some ideas to see if there are Technical service bulletins (TSBs) out there. My simple logic and searching has shown that other people have similar problems around the US, just gotta search it out

[Hafnutz]

Try removing the battery cable when you park it and hook it up in the morning when you want to start it. That will tell you whether you have a major parasitic draw or if it's just the battery. I have an F-150 and it's been pretty good so far. Better yet bring it to a Ford dealer and let them keep it for a couple days. Wiring problems aren't that hard if you have the proper schematics and test equipment many of the smaller shops don't have...

[deadeye]

1+ on taking it to the ford dealer. Im thinking the other shop missed something bigtime. If its big draw like that it should be pretty easy to spot.

You would also do yourself good by going to a auto parts store and having them check your battery. Oreillys does it free and I know the tester they got puts a load on the battery besides running voltage tests. I know you said that the shop checked it but I have seen a battery pass a voltage test to fail a load test so if they didn't do all the work it might still be bad.

If your feeling ambitious, you got a couple hours and 5 bucks for a test light its not that hard to find a draw. Hook up the tester inline between the negative cable and battery terminal. Start pulling fuses and you will find whats drawing power when the light goes out. It might take ya a couple hours but it would at least give you a good idea of what is taking power.

With a truck that new I would think ford would want to see it so they could figure out a potential problem. Even though its beyond mileage it would be worth bringing it in to see if they will do something for you.

[CaptainBly]

Beat me to it deadeye, I was thinking the same thing about the test light. Done it before and worked.

[Jeremy airjer W]

You need to know what ford does before you try the test light. Seems to me they can have things powered up for up to 45 minutes on some of them! You could literally be chasing your tail for nothing if you don't know.

A test light is highly inaccurate and unless your familiar with your test light the average person would not be able to tell the difference between an acceptable draw and an unacceptable draw.

The most accurate way to know is using and amp meter hooked in series. Hook it up and walk away for a half hour or so and then check the reading. You should see less than .050 amps and more like less than .030 amps. Anything more is a draw and then you can start pulling fuses.

Things like aftermarket radios and courtesy lamps are really common.

I also like the suggestion of disconnecting the battery over night and seeing if it starts. A battery that has been discharged that many times is probably sulfated and is no good whether there is a draw or not so plan on replacing it.

[Scott K]

I agree with Airjer, dont use a test light, use only an amp meter. First thing to do is trip the door latches so they are in the closed position, so you can get in the truck without re waking up the modules. The modules on Fords stay awake for upto 1 hr, but most go to sleep within 20 minutes. Make sure the key is out of the ignition, make sure the hood light isnt on, then hook the amp meter in series with the negative battery cable and walk away for 45 minutes, comeback and see what the meter is reading, anything over 50 ma is excessive. Start by pulling fuses out, 1 at a time until the meter drops below 50 ma. Another thing, once you pull the fuse, dont reinstall it, until you are done. So make note what fuses came from where, I usually just take a picture of the fuse box for reference.

One other thing that would be helpfull is to pull codes out of all of the modules to see if there is one that is giving some hints to what is going on.

[Jeremy airjer W]

Just remember to pull the door handle to release the latch before slammin the door shut!

[deadeye]

Well there you go, the professional way to do it! . I guess the old school stuff doesn't always work on the newer trucks. I did the old test light trick to find out my radio was drawing lots of power on my blazer and it worked ok but I could see where the multimeter would be mint. Never thought of using that.

It would be wise to pull relays too since some of them are always hot, right?

I remember having a cooling fan relay that was shorted out that would draw the power down. (it did keep the fan on all the time so that was a dead give away). Other relays might not be so obvious though.

[Jeremy airjer W]

Everthing is fused including relays. Pulling fuses is probably the fastest way to narrow down the possibilities.

[HondaRider07]

so for the past couple months, i have been driving my step dads 2008 f 150 king ranch edition. it has a lot of miles on it (past warranty), but thats cuz my step dad drove from central iowa to northern MN a bunch of times over the last year, so the truck is still in really good condition.

anyways, about 2 months ago when it started getting cold, i went to start the truck one night after class and it wouldnt turn over. so i got a jump and drove it home and it did it a couple more times within the next couple days, so i took it in to a place to have them look at it. they told me there was something that was drawing power from the battery and not turning off when the truck was turned off, and they were going to have to pull fuse by fuse to find out which one it is. $250 later, they tell me it was the heated seats that werent turning off and causing the battery to die. so about a week later after they pull the heated seats fuse, it does it again. over the past month when it has been really cold, the problem has been happening more and more frequently. i have a jump pack in the back of the truck, so its not THAT big of a deal when i have to jump it, but it sure is a pain in the pink flamingos when i have to keep doing it everyday, especially in this cold weather.

does anybody else have this problem with their f 150? or has anybody heard of this problem happening to f 150s? this truck is only a year old, so it should be able to START in the winter. i could go get a beater car for $500 that would start more frequently then this one year old truck. i know i obviously need to bring it in again to find out what else is drawing power from the battery, but i was hoping someone on here might have heard of this problem before and could help me out. i dont know hardly anything about cars/trucks besides how to change oil and a tire.

thanks for the help!

Needs a battery, all these newer f150's were shipped with under powered batteries for northern winters. We see it every winter at the dealership. Go to sears and get the biggest battery that will fit in your tray. Anything over 800 CCA is sufficient.... If you want to get further into it, you can do a drain test on the electrical system. Anything less then 50ma of draw after the truck as sit for over an hour is good.

[deadeye]

Thanks airjer. I could have sworn that some of the relays were hot from the battery. IDK why I didn't look further into that. I know some of the aftermarket stuff I have seen is hot so I guess didn't think about it more. Everything should have a fuse though.

The great thing about this forum is that Im learning as each question rolls in. Gotta say thanks for that!