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Discussion Starter · #1 ·
Hello e46ers,

I would appreciate any help on the problem below.

Car: 2001 330xi, Premium Package (cold weather, premium wheels, 6-spkrs stereo), bought new in Mar 01

Problem: every now and then I wake up one morning to find that my car wont start. The battery is completely discharged - the flashing lights and clicking sound. This has happened, oh, about 4 or 5 times.

History
1. First time it happened - March 08, I replaced my 7 yrs old original battery.
2. Happened again a few months later - took it to my mechanic - said busted alternator - replaced that.
3. Happened again - mechanic said bad battery. Hmmm... how likely is that? Anyways thinking I had bad luck, exchanged the battery for another brand new one
4. Happens again - I ask mechanic to check out alternator - see if they got a bad one. He checked it out and claimed it was fine - problem with battery and replaced 2 brand new battery. Also advised me to drive the car more (I was doing less than 20 miles a week).
5. Things hum along well for about 3 months and now the problem has recurred. And despite driving > 100 miles a week.

Additional info:
1. After installing the very first new battery I would hear a humming sound. After having searched the forums today I suspect it was the bad alternator.
2. The few times that it has happened the closest correlations I find are to extreme weather (very cold or hot) and leaving A/C and/or radio "on" upon shutting down the car.
Been searching the web everywhere and did come across these:
http://en.allexperts.com/q/BMW-Repair-805/2003-bmw-x-5.htm
http://en.allexperts.com/q/BMW-Repair-805/battery-discharges.htm
that point to: stuck trunk light (unlikely in my case), "a faulty/bad connection in the main junction box where the heavy battery/alternator cables meet", "Most common problems are the A/C final stage blower resistor coming on by itself or the electrical portion of the ignition changing key position on its own"

I also read somewhere about climate control potentially playing a role. If so, I would suspect climate control and/or AC are primary culprits. It seems to happen more often in hot weather.

Can anybody advise me what to do? I am *not* a hands-on car person (although I wish I were). But I dont think my mechanic is going to find the underlying issue (or even want to) and sense that the stealership is the answer. But I would like to take a shot at narrowing the problem further - and maybe even fix it myself. I think there is a parasitic power consumer that turns on/remains on after I shut down the car.

I would appreciate any and all guidance.

Best,
- bm

:banghead:
 

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The Final Stage Resistor was the culprit in our case.

However, another common culprit is the engine cooling electric fan staying on or coming on when the car is off and staying on till the battery is drained.

You can search more on those topics and see if you find similarities in symptoms.
 

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Discussion Starter · #3 ·
Thanks TKC! I appreciate the response - I hope my issue is the same. I found a DIY on the FSR but I have no tools etc - I am going to check with my mechanic. I also posted on the FSR DIY post asking for additional confirmation.

Thanks again!!

:thanks:
 

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For the sake of your wallet and our DIY community, dont get a mechanic to do that! Although the space is tight, you need only ONE (ok, two) tools to get the FSR replaced. It is not difficult to perform the repair ... its just tough to get into the small space. You need a screw driver and the proper size Torx. Please, DIY!!!!!!!!!!

FYI ... I paid about $50 for my FSR and installed it myself. You would be looking at 200 or more to have a mech put one in. Once you see the work involved (read: or lack of), you will thank me for suggesting DIY.

Anyway.. for troubleshooting- If the FSR is failing and causing a battery drain, I assume it will be because the fan was turned on unintentionally by the FSR. Put your ear to the vent in the hood and see if the humming is coming from there .. see if air is coming out of the hvac vents when the ignition is off. if so it is certainly your blower and therefore the FSR. Also look for the fan acting weirdly when you first turn on the car (with fan on). Any other odd behaviors by the fan would confirm it is indeed the FSR.

The cooling fan will also be very easy to check.. obviously.

I found a DIY on the FSR but I have no tools etc - I am going to check with my mechanic.
 

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yeah, remove the glove box and check for it being hot, if your battery is dead and that sucker is warm, there is the culprit :/

btw, I wouldn't take the car back to the same guy that replaced the alt. and two batteries for the same issue, just sayin' lol
 

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Discussion Starter · #6 ·
That wd mean I have to wait for the thing to die again. It is quite sporadic. I have been turning off the climate control before shutting down the car.

Do you suggest I confirm using your method?
 

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Discussion Starter · #7 ·
easyIsel - I would love to do it but here are my two issues:
1. I dont know what tools to even get! I dunno what Torx is and neither do I know the sizes reqd
2. I am afraid of dropping those screws/nuts etc in the car into soem crevice or space where I cant reach them. Then I am s*****d
What do you think?

For the sake of your wallet and our DIY community, dont get a mechanic to do that! Although the space is tight, you need only ONE (ok, two) tools to get the FSR replaced. It is not difficult to perform the repair ... its just tough to get into the small space. You need a screw driver and the proper size Torx. Please, DIY!!!!!!!!!!

FYI ... I paid about $50 for my FSR and installed it myself. You would be looking at 200 or more to have a mech put one in. Once you see the work involved (read: or lack of), you will thank me for suggesting DIY.

Anyway.. for troubleshooting- If the FSR is failing and causing a battery drain, I assume it will be because the fan was turned on unintentionally by the FSR. Put your ear to the vent in the hood and see if the humming is coming from there .. see if air is coming out of the hvac vents when the ignition is off. if so it is certainly your blower and therefore the FSR. Also look for the fan acting weirdly when you first turn on the car (with fan on). Any other odd behaviors by the fan would confirm it is indeed the FSR.

The cooling fan will also be very easy to check.. obviously.
 

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There are ways to address your concerns. here are my personal inputs:

1. Click "User CP" in the forum, click "Edit Options" on the left, nd look for the drop-down that sets "How many posts are shown per page" on the right. I tweak that all the way to 100 so I dont have to flip pages constantly when reading throguh threads.

Next, read through the FCR DIY you posted in, from first post to last. Knowledge is power (and will ease your concerns to boot). In there somewhere someone will specify what the proper Torx size is. .. not to mention all the other helpful tips people provide to you.

(Torx is simply a different type of screw head, looks sort of like a star. Buying the whole Torx set vs. just the right size is a good idea, since lots of bolts on your car are Torx heads.)


2. You can buy new bolts from any dealer, thats not a problem and they are inexpensive. I can even get you the part # for them for you (via realoem.com).

I would recommend a "magnet on a stick" tool. Invaluable helpful during other tasks Ive done on my car. In a pinch you can make your own with a fridge magnet, some electrical tape, and a coat hanger. you should be able to grab a lost bolt with that. Further, You can use Heavy Duty tin foil to cover any holes you fear you may drop them into.

It wont be a catastrophic mistake to drop a screw, just add some frustrations into the mix. This isnt rocket science, its very straight forward- just a tough reach.

With all that said, if you still feel uneasy or unsure, no one wants to force you. Go ahead and let a mechanic rape you, sometimes it IS necessary :4ngie:

easyIsel - I would love to do it but here are my two issues:
1. I dont know what tools to even get! I dunno what Torx is and neither do I know the sizes reqd
2. I am afraid of dropping those screws/nuts etc in the car into soem crevice or space where I cant reach them. Then I am s*****d
What do you think?
 

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That wd mean I have to wait for the thing to die again. It is quite sporadic. I have been turning off the climate control before shutting down the car.

Do you suggest I confirm using your method?
Even turning off the climate control may not be enough. That FSR has been proven (through posters experiences in that FSR DIY thread) to sometimes fail in a way that causes the fan to come on and STAY ON even without the key in the ignition, without you anywhere near the car.

Yes if the FSR is warm with the car off for a long time, it could be the problem. But even if it isnt warm it still could be defect. Doesnt hurt to check it, but I would replace it, since you will be in there anyway, and it will solve the sporadic fan problem you arleady have (which indicates a bad FSR).

Also I would agree with one of the posters above, dont bring your car back to the same mech that keep replacing the same parts for the same problem. No troubleshooting skills what-so-ever !! I work in technical support so troubleshooting is like, built-in to my brain at this point. Common sense does = troubleshooting skills most of the time.

If you disconnect one of your battery cables, and wire a multimeter in amperage (current) mode between the cable and your battery, it will display how much current the car is using. If its a lot, pull fuses until the usage drops to normal levels. Whatever causes it to do that is the cause of your battery drainage.

There are many ways to troubleshoot! Many without spending a lot of money.

With that... I've been posting a bit much on this thread so thats all from me. Good luck!! We are here if you have any issues :hi:
 

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Discussion Starter · #10 ·
FSR replacement did not help

OK guys I am back to report that replacing FSR did not do the trick. Disclaimer - I did not do it myself primarily due to time constraints - I had a mechanic replace it for me. He also checked the alternator/regulator and said it was good.

But I am still suffering from the battery discharge problem. I am a little at my wits end :banghead: and believe next step may be for me to start pulling the fuses, like easyIsle mentioned above. The problem is I dont know where to start. Could someone point me to some schematic etc of the E46 that I could use , please?

Thanks very much in advance!
 

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If you disconnect one of your battery cables, and wire a multimeter in amperage (current) mode between the cable and your battery, it will display how much current the car is using.

then start pulling fuses one at a time, watching the multimeter each time. You need not a schematic because you will be pulling every fuse one at a time. You might only need a notepad to record which fuses you have pulled and what the current drop was.

Do this with the door of the car shut so the lamp in the car is not on. Or hold the interior light button for 3-5 seconds until it shuts off (service mode)

You did replace the battery,right?
 

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If you disconnect one of your battery cables, and wire a multimeter in amperage (current) mode between the cable and your battery, it will display how much current the car is using.

then start pulling fuses one at a time, watching the multimeter each time. You need not a schematic because you will be pulling every fuse one at a time. You might only need a notepad to record which fuses you have pulled and what the current drop was.

Do this with the door of the car shut so the lamp in the car is not on. Or hold the interior light button for 3-5 seconds until it shuts off (service mode)

You did replace the battery,right?
what are the normal numbers to do this? or how to read this numbers?
 

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I dont know about normal numbers and you dont need them

Lower is better. Your reading will be in mA or milliamperes. I would guess roughly that 100 mA or less is good.

We know yours is too high if you have a new battery but your car cant keep a charge. So run the test and find what is causing it to be such a high draw. A big drop in the reading is what your looking for.. that is the troublesome circuit

Once you ID it then you can go about fixing it.
 
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