Electrical Problem, dead battery

[coghij1]

I've come to the conclusion that something is draining my battery while the vehicle is turned off. I've been getting surviving on my 2nd brand new battery by removing the negative battery cable every time I turn the car off. So far so good. But I NEED to FIX it!

I've tracked it down somewhat... With the vehicle turned off I removed the negative cable and stuck a tester light in series between the cable and battery terminal. The light turned on so I began pulling fuses to see which fuse series is running. Pulling the fuse in use should turn off the light, correct? So I get to fuse 20 inside the passenger compartment and the light goes out. Fuse 20 runs "PATS, Driver seat switch, Memory switch, Driver seat module, BSM, Sunload sensor." So now without that fuse (5 amp) in, my battery isnt being drained.

I just have no idea where to go from here... Any suggestions??? I dont know how to check the Passive-Anti-Theft-System. I dont even know what the BSM or Memory switch are!

 

[my1zamboni]

I may be wrong, but that fuse should be running with the X off.
Your passive system is your alarm/anti theft. it seems it would be pointless to not have it running while you are not with your X.
Did you stop at that fuse or did you continue to check the rest of the fuses? I think you are on the right path checking it like you are, but keep going past that fuse and check them all.
I had a battery issue also that seemed to be all cleared up after I unplugged my gps every night (after market not in the stereo) and also did this fix in the drivers door
http://www.explorerforum.com/forums//showthread.php?t=270081
Not sure if they were related but I had killed a brand new battery back in July and haven't had any isues since. Good luck.

 

[BigRondo]

I agree with my1zamboni. Check for broken/damaged wire(s) in the boot between the body and the driver's door.

A lot of issues can be traced back to broken/damaged wire(s) in the boot between the body and the door. I found a broken wire and repaired it and all is back to normal!

Could also be related to the door ajar switch.

In addition to the link he posted, here is a great thread for removing the door panel and checking/replacing the door ajar switch, thanks to borland for the awesome write-up: http://www.explorerforum.com/forums/showthread.php?t=249253

 

[imp]

Much more helpful than a tester in series at the batt. is a DC Ammeter. A very small current drain is constant with these vehicles, the PCM requires a bit of current all the time, as well as, I'm sure, things such as the airbag module and PATS system. Word of caution: initially, when connecting the batt. cable, a fairly large, very short-term current will flow which brings airbag back-up power supply back up to voltage. To save ammeter damage from that surge, I would connect the meter to the batter cable terminal, and the batt. post (below it) while the batt. cable is connected to the batt, then slip it off the post, leaving the meter in series with the cable and batt. post.

Before PATS, (i.e., EEC-IV system) I used to measure about 0.005 Amp. (5 milliamps) as the typical computer drain. To "empty" your batt. say, overnight, at least several amps. must be flowing constantly. If that is happening, those amps. are generating heat somewhere, no doubt about that, not a good thing.....imp

 

[coghij1]

Thanks. I did what you said imp, I used a meter and measured a 0.22-0.25A drain from the battery. Would this be enough to cause a complete battery drain over 10 or so hours?

I also took a measurement with fuse 20 pulled and only read a 0.02A drain. What do you think?

 

[my1zamboni]

After reading what IMP has said and your reply, I would look real good under the seat.
That is also a common place for wires to short as you (or previous owner) could have hit them cleaning under there, storing something under there, etc. It is very possible to have a short under there also from over streched wires. Another reason I would start there is it is the easiest to get at, eliminate the easy simple things first.
You did mention that this fuse runs your master seat switch so that would be another reason to start there.
You never did mention......what year is your truck?

 

[coghij1]

2002 XLT 4WD V8 4.6

I will most definitely tear around underneath there. Probably not until tomorrow though (my day off). Hopefully I'll have the time and patience to find something. Thanks again.

 

[my1zamboni]

Coghij1 I did a bit more research for you (and me as I am curious also) BSM is "body security module" and if my research is correct this controls your keypad and also your "PATS" (passive anti theft system) and your sunload sensor has something to do with A/C and recirculating air in the cabin, the sensor itself seems to be in the dash (on top under the windshield) I have read about people having a bad BSM in this forum somewhere but can't seem to find it. Your BSM should be if you are sitting in rear passenger seat down below your right hip behind the trim panel.
Good luck again and hopefully I didn't confuse you more, I am just trying to help you out a bit. Keep us informed.

 

[BigRondo]

In accordance with my1zamboni's post, check out this thread for locating the security module, thanks to Welli for a great write-up!!: http://www.explorerforum.com/forums/showthread.php?t=246957&highlight=entry+code

 

[imp]

Thanks. I did what you said imp, I used a meter and measured a 0.22-0.25A drain from the battery. Would this be enough to cause a complete battery drain over 10 or so hours? 1/4 amp. should not drain a good battery in 10 hours, I would think, but a batt. need not be "dead" to prevent it from cranking over an engine. Then too, how old/what condition is your battery?

I also took a measurement with fuse 20 pulled and only read a 0.02A drain. What do you think? Fuse 20 according to my wiring diagrams does indeed feed four things: Power Seat Switch Left, Autolamp (sunload sensor), Driver Seat Module, and Vehicle Security Module. Now, 0.020 amp. (20 milliamps) is a reasonable current drain for the various "keep-alive" functions in processors (computer, etc.). So you have narrowed the culprits down to 4 possibilities, as we see it. Now, which would likely be able to "waste" almost 1/4 amp. (that comes to about 3 watts of power), without causing overheat, charring, fire (!), etc.? I'm guessing any but the power seat switch. Why not locate these little devils, disconnect them one by one, checking your ammeter each time, and see if one of them is causing it?

I tend to hesitate to think about chafed or damaged wiring in the harness, like under seat, as usually that constitutes a short-to-ground which will carry a helluva lot more current than 1/4 amp, and "take out" the fuse feeding that location (in this case F-20, 5-Amp. fuse)

You may qualify as an Electrician after this little fiasco! Good luck! imp

 

[coghij1]

Well I just came across something interesting.... After driving home from work, I let the car sit for an hour. After an hour I tried that trick again where I got my meter ready and stuck one probe on the cable and touch the other to the bottom of the battery post and carefully removed the cable. This time I read 11-17 milliamps! So Im guessing either one of the computers "occasionally" isn't going to sleep or something else is being temperamental...

Update: I pushed the unlock button on my remote and after all the lights turned back off on their own I took another measurement. This time it was 0.22 amps again. So I guess the real question is can that kill a battery over night if the PATS never goes back to sleep? Im thinking there is another problem though.

 

[matt0248]

Well I just came across something interesting.... After driving home from work, I let the car sit for an hour. After an hour I tried that trick again where I got my meter ready and stuck one probe on the cable and touch the other to the bottom of the battery post and carefully removed the cable. This time I read 11-17 milliamps! So Im guessing either one of the computers "occasionally" isn't going to sleep or something else is being temperamental...

Sometimes computers go to sleep after a while. So turn the key on and back off to see if the current changes. then check it again after 5, 10, 15 minutes.

 

[my1zamboni]

Also you PAT shouldn't "sleep" it is your anti theft.
It should sleep while you have the key in, if it is "sleeping" it can't watch your car.
I do agree with IMP that it isn't a short, after reading his reply, I agree and think a short would blow a fuse, like he said, unplug one thing at a time and retest.
Electrical problems suck and are tough to find.
I wish you luck with it.

 

[coghij1]

Im pretty sure that whatever was happening to drain the battery hasn't been happening lately. I've been leaving the battery attached overnight, since after an hour of sitting, the draw has been only a few milliamps (I've been keeping tabs on it).

In other words the problem has disappeared from the radar. Of course there is always a chance that Im an idiot and somehow didn't notice a light or two left on, thus causing all my "electrical" problems. I just really doubt it. Only time shall tell I guess...

 

[coghij1]

Here is a follow up in case anyone reads this again. About a month ago I was having the "door adjar" problem that was mentioned above. It went on for about a week while we were having really mucky weather here in Phoenix. By the time I was going to get around to fix the switch, the weather cleared up and the problem went away for now. I think I read somewhere on here that humidity contributes to the switch acting up and Im getting the feeling that the door adjar switch is what was causing all my earlier battery drains (interier lights prob stayed on). Here in the desert we only experience humidity a few days a year so it makes sense considering the problem popped up and dissapeared the way it did.

 

[BigRondo]

Thanks for the update. It helps others that are having similar problems. Have you tried spraying the latches with WD-40?

That is a great write up.

On a side note, before going through a complete replacement of the switch, you can spray WD40 into the door latch opening on each door, as these become stuck sometimes....and this can alleviate the issue.

This worked for me, after going for more than a year of the "door ajar" light coming on occasionally...mainly after a car wash, high humidity, or rain....making me unable to lock/arm the vehicle from the door keypad and keeping the dome lights on. Worth a try....it worked for me

 

[coghij1]

I have not but I will do that first. I probably won't know if that helps until the next storm though. Thanks.

 

[BigRondo]

An ounce of prevention................................

 

[coghij1]

So I've had a "dead Battery-like" condition a time or two since I last replied. The very strange thing is I go to start and get the single click. The analog gage on the dash will show nothing and the lights wont even work (not even dimmly). BUT when I first hopped in to start her up, the interior lights came on when I opened the door and I got the ding noise when I first put the key in the ignition (cuz my door was still open).

Both time this occured I though "aw shiz, stupid sonofa..." and popped my hood. The first time I just gave my battery and wiring a blank stare. I got back in and wallah! It started up like nothing was ever wrong! The second time it happened to me (just 2 days ago) I got the"click" and saw all my gages drop to nothing as usual, then just popped my hood and tried starting again. It worked again.

I am clueless as to why it's giving me fits. I don't think it's the ignition because I can try pulling the key and re-trying multiple times with absolutely nothing. Only when I pop my hood does it reset whatever is going on.

 

[DryDog]

I have a 04 X Eddie B with 80K, and a year old Optima red top. 2 weeks ago a got a wa-wa after not driving it for a couple weeks. I have found there is a 0.26A draw until I pull fuse 2. My owners manual show F2 as BSM. Do you know if mine also controls Power Seat Switch Left, Autolamp (sunload sensor), Driver Seat Module, and Vehicle Security Module, or just BSM?