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X3 E83 (2004 - 2010)
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  #1  
Old 01-17-2017, 04:41 PM
XionUAV XionUAV is offline
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New Alternator, Battery, Still Won't Charge, No Battery Light - SOLVED

My son's 2004 X3, 2.5i died this morning on the freeway from an obvious voltage brownout. He managed to get to an Auto Zone where they tested the battery and found it was totally dead and bulged. They installed a new battery for him and he made it to my house. I checked the voltage at the battery and it was just under 12V while running. He said he's never seen the battery light ever come on.

I replaced the alternator this afternoon and it still won't charge and there's still no battery light. He turned the diagnostic function on and it shows about 11.5V, which is what my meter shows. Still, no battery light.

We're about to take it to an independent BMW shop but I wanted to see if anyone here has any ideas first As I understand it there's an exciter circuit that monitors the voltage and tells the alternator what level of voltage to put back into the battery.

Clearly there's a malfunction in the system that monitors the voltage and controls the output of the alternator. I work on mostly Audi and VW so I'm at a loss with this one. Any ideas would be greatly appreciated. Thanks.

Last edited by XionUAV; 01-18-2017 at 01:20 PM.
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  #2  
Old 01-17-2017, 05:40 PM
BMWaufKS BMWaufKS is offline
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Ground straps. Search here. (But could be many other things instead.)
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  #3  
Old 01-17-2017, 06:45 PM
XionUAV XionUAV is offline
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I searched and found nothing relating to a similar problem on the X3. Without a place to start specifically, a person could spend a month chasing his tail which my son and I don't have time to do because it's his only vehicle. Found similar issues with other models but without info on this particular model just guessing or poking around is pointless. Of all the vehicles I've worked on a bad ground has never been found. Usually it's component failure. I suspect that's the problem here but don't have a shop manual or the correct diagnostic software to track it down as I work primarily on VW/Audi.

An electrical diagram would help but we'll probably just take it to a shop tomorrow and let the pro's earn their money. He's kind of done with it anyway because of all the gremlins it has so it will likely become someone elses glitchy, oil-dripping baby pretty soon.
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  #4  
Old 01-17-2017, 07:05 PM
swampX3 swampX3 is offline
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charging system is not special

>.....don't give up.....if you can test ground and the voltage regulator on a vw or audi etc you can easily do it on any bmw cause they are essentially the same.....even the major parts like alternators come from the Bosch house or a close relative like Valeo

>you can easily rig a temporary jumper cable ground from the engine lift hook to the hexagonal ground point on the inner wheel

>what make of parts have you bought for it ....did they just swap the alternator without a new voltage regulator
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  #5  
Old 01-17-2017, 08:46 PM
XionUAV XionUAV is offline
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I diagnosed the original alternator as not charging simply because there was low voltage at the battery and replaced the alternator myself. Alternator and regulator as one unit. There was no change in voltage with the new alternator so the problem isn't the alternator and likely never was. Doesn't mean it can't be something related to the alternator though.

My son left the vehicle here and took one of my cars so I just did a test that was interesting. Key on and the battery light lights. Key to start position and the battery light goes out after the first compression stroke and the vehicle fires on the third or fourth stroke. So it appears the voltage sensor and control circuit might be working and getting voltage. But if it is, why would the on-board diagnostics show the same low voltage I saw at the battery unless the voltage sensor was at the battery?

There are two cables running to the positive side of the battery. Does anyone know if the smaller cable is from the alternator? Logically it would make no sense to run it all the way back there from the front but since when do auto engineers always make sense? If the alternator is actually working and its output is going to the sense and control circuit but not getting back onto the main bus and back to the battery, that would cause the problem we're seeing. It doesn't seem likely but I'll check the voltage directly at the alternator tomorrow morning before sending the car off for repair.

The other thing that would be nice to know is what the small clam-shell cover next to the positive post at the battery is with the yellow plug and two black wires coming out of it.

Last edited by XionUAV; 01-17-2017 at 08:48 PM.
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  #6  
Old 01-17-2017, 10:01 PM
Supercourse Supercourse is offline
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Quote:
Originally Posted by XionUAV View Post
The other thing that would be nice to know is what the small clam-shell cover next to the positive post at the battery is with the yellow plug and two black wires coming out of it.
That's BMW's "Battery Safety Terminal" (BST). I doubt that is the problem so would advise against disassembling it - expensive to replace.

This auto recycler video explains it, but is calling it a "battery terminal" instead of a BST.


I'd look for high resistance somewhere else in the charging circuit.
Did you definitely rule out the cable connection at the alternator?

Not sure what would have caused the original battery to bulge.
Isn't that usually a sign of over-charging?

Did Autozone connect the vent tube up to the new battery?

Last edited by Supercourse; 01-17-2017 at 10:08 PM.
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  #7  
Old 01-17-2017, 10:28 PM
XionUAV XionUAV is offline
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Ah. That makes sense. I had read the terminology somewhere but didn't correlate it to that device. Thanks for the video link.

The cable at the alternator, and the terminal, are clean and in good shape. Won't test the voltage out of the alternator until morning. The real clue here is the battery light. If that circuit is working properly then the alternator must be working. Otherwise the light should come on indicating the charging system has failed. As mentioned, the light does come on with the key in the "on" position but goes off when the car starts and stays off. That's the strange part.

The battery bulging was likely caused by the battery being very weak and super cold temps. Over the past two weeks the temperature dropped to -15 degrees and stayed around 0 several nights. That coupled with the low voltage or charge probably froze the thing.
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  #8  
Old 01-17-2017, 10:38 PM
Supercourse Supercourse is offline
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Ah, yes, forgot about electrolyte freezing when battery is in very low state of charge.
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  #9  
Old 01-18-2017, 04:36 AM
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Burning2nd Burning2nd is offline
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I HAD this happen once on a acura, There something along the line of a ELP circuit (electrical load protection)

there was a O2 wire that had melted to the exhaust causing a short to ground so it popped its fuse to not allow the car to charge...
like a way of protecting it self from self electrocution I know bmw has something along the same line, Im not sure of what its called or how they did it..

Id take a good look at the fuse's
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  #10  
Old 01-18-2017, 06:10 AM
swampX3 swampX3 is offline
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BMW wiring diagrams

>this link looks like its live again for your wiring diagrams

http://www.bmw-planet.net/diagrams/release/en/
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  #11  
Old 01-18-2017, 07:11 AM
swampX3 swampX3 is offline
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2004 x3 battery basic one line electrical

>see attachment
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  #12  
Old 01-18-2017, 08:49 AM
XionUAV XionUAV is offline
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Quote:
Originally Posted by Burning2nd View Post
I HAD this happen once on a acura, There something along the line of a ELP circuit (electrical load protection)

there was a O2 wire that had melted to the exhaust causing a short to ground so it popped its fuse to not allow the car to charge...
like a way of protecting it self from self electrocution I know bmw has something along the same line, Im not sure of what its called or how they did it..

Id take a good look at the fuse's
Checking every fuse I could find using the continuity tester on my DMM was one of the first things I did after installing the new alternator. That included the big ones in the black box just off the battery. That doesn't mean there couldn't be a burned fusable link somewhere if BMW uses those.
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  #13  
Old 01-18-2017, 08:50 AM
XionUAV XionUAV is offline
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swampx3, excellent info. Thank you. I'll take a look at those and go do some testing pretty soon.
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  #14  
Old 01-18-2017, 09:57 AM
swampX3 swampX3 is offline
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download free rheingold ...it has all the electrical drawings

>rheingold for the bmws ....start with post 7 and fan out....it has all the electrical drawings and repair steps in it

>post 8 shows how to request the link from the FEST site

http://www.bimmerfest.com/forums/sho...=1#post9972460

Last edited by swampX3; 01-18-2017 at 09:58 AM.
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  #15  
Old 01-18-2017, 11:31 AM
XionUAV XionUAV is offline
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I requested a link.

Interesting test I just did. Measured the voltage at the back of the alternator running and stopped and it's zero volts either way. Unless this design is completely different than pretty much every other car I've ever worked on, the battery positive side should be bonded to the alternator output cable somewhere. So running or not it should still show battery voltage. Time to dig in I guess.

What still bothers me though is why the battery light is not coming on if the alternator is putting out nothing. That makes no sense.

I had a Saab repair bite me one time because after replacing the alternator for a no-charge condition, it still didn't charge. A continuity test of the alternator to battery lead showed it was open. Found the cable corroded in half under the battery tray. Ran a new cable directly from the alternator to the starter post, which is connected directly to the battery of course, and problem solved.

I'll post what I find or don't find.
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  #16  
Old 01-18-2017, 12:06 PM
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Doug Huffman Doug Huffman is offline
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Quote:
Originally Posted by XionUAV View Post
Unless this design is completely different than pretty much every other car I've ever worked on, ...
It is.
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  #17  
Old 01-18-2017, 12:13 PM
XionUAV XionUAV is offline
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Well fortunately the charging system isn't, for the most part. I removed the plastic undercarriage pan and followed the alternator cable back to the starter where it bolts to the main post along with the battery cable. The nut on the post was loose so the terminal ends were loose as well. The starter is pretty shiny so it must have been replaced sometime before my son bought the car about 1 1/2 years ago. Glad it wasn't me. That starter looks like a pig to replace.

I'll clean the terminals and reattach them properly. Hopefully my next post will be good news.
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  #18  
Old 01-18-2017, 02:04 PM
XionUAV XionUAV is offline
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Solved!

Cleaning and reattaching the terminals did the trick. It's charging fine now.

The problem was the installation of the starter. The plastic guard around the post was slightly higher than the top of the lower nut where the terminals were seated. They were originally tightened on at an angle keeping them from seating directly on the lower nut and the top nut worked loose. I placed a washer on the lower nut which let the terminals seat just above the plastic and could be tightened down properly.

This X3 has about 170k miles and it's the 6-speed manual so spending $300 for a new battery, alternator, belts and air filter is fine. Imagine what the repair cost would have been at a dealer even without a new alternator. Last year I replaced the valve cover gasket but it still leaks like a sieve from around the block somewhere. Haven't spent the time to find that one yet.

It still bugs me why the battery light circuitry was designed such that no output from the alternator wouldn't activate the light when the link to the battery was severed. Just one of those things where I guess the charging system had to still be connected properly to generate a fault.

Anyway we're good for now. Thanks to everyone who contributed.



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  #19  
Old 01-18-2017, 04:12 PM
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Burning2nd Burning2nd is offline
Under the lift arms
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PFFFF THAT coolant tank... just ordered that and the upper and lower hose.. 176$ shipped
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  #20  
Old 01-19-2017, 06:14 AM
jlex jlex is offline
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Good for you. How in the world did you ever access that starter? When I had my intake manifold off on my '05, I replaced the starter at 100,000 mi as a preventative measure. Don't know if I could have even laid eyes on it without removing the manifold. Your picture shows it pretty clearly, though.
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  #21  
Old 01-19-2017, 08:16 AM
abscate abscate is offline
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You need to replace that whole cooling group - that is leaking coolant and that aint good.

IF thats the original air bellows, that will be cracked too, but you have to remove it to see that. The clamp on the Throttle body can be a pig to reach, but its doable from up top
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  #22  
Old 01-19-2017, 11:14 AM
BMWaufKS BMWaufKS is offline
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Yes, no offense intended, but from that picture this X3.1 has a lot of "deferred maintenance." So plenty more to do, including the ground straps. Glad you found that weakness in the charging circuit.
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