# alternator is good, battery is good, battery not charging............ HELP!



## tombugby (Nov 27, 2011)

so last week i was driving along in my beetle when the ABS light came on and then the brake light came on and the car died. we pushed our selves off of the road and got a tow, once i got the car home i plugged my diagnostic tool in to read the codes and find out what happened..... no codes. then i realized that my battery was low so i charged it up and ran another diagnostic, still no codes and when i took the car for a spin it acted fine. so i did a little reading and found out that when your battery isnt receiving a charge the ABS light comes on and the car dies. well my first thought was the alternator so i pulled the alternator and took it in to get it checked. they told me that the alt was fine so i brought in the battery to see if it was bad, it was fine too. so the battery is not getting the energy that the alternator is putting out. i dont know what the problem is..... the only thing is, right before this happened i replaced the water pump in the car myself and the brake down was the first drive after the water pump replacement. up until that point everything was fine with the charging system. can anyone help me?


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## MyOtherRidesAVette (Nov 13, 2010)

As complicated as VW has made the entire elctrical system on their cars, the charging system is the simplest of simple. The alternator puts out the charge, the battery receives it. Via one direct path through the main fuse box which sits atop the battery. If the alternator is not charging the battery it will (should) trigger the "generator" warning light on your instrument cluster, the warning light many incorrectly refer to as the "battery" light. If the battery is bad, you will not get a light (and no codes). You say both have been bench tested, out of your Bug. The normal way to test an alternator is a load test, while in the vehicle, with the engine running.

The ONLY things that can fail are
1) the Alternator
2) the Voltage Regulator (an integral part of the Alternator which limits the voltage going to the battery)
3) the Battery
4) the wiring that delivers the current from point "A" (alternator), to point "B" (battery), including the main fuse block atop the battery

No DTCs (Diagnostic Trouble Codes) will be thrown with the failure of any of these components.

For the moment lets assume you are correct in your diagnosis that the Alternator/Voltage Regulator, and the Battery are good. This leaves only a problem with delivery. The components of the delivery system are
1) Alternator to body ground, accomplished through the mounting
2) Battery to body ground, via battery cable, check both ends for CLEAN and TIGHT, and integrity of cable
3) 25.0 mm² (+/- #3) Black Cable from Alternator to Battery Box Fuse Position [S177], check both ends for CLEAN and TIGHT, and check for integrity of cable (this is a problematic lead in the NB)
4) Fuse (Position [S177]), amperage determined by alternator size
5) Fuse Block (this is also problematic, subject to melting, in the NB), check for any visible damage
6)16.0 mm² (+/- #5) Red Cable from Fuse Block to Battery check Battry connect for CLEAN and TIGHT and check for integrity of cable

I would have a look at this link 
http://newbeetle.org/forums/questio...-someone-else-org-battery-fuse-box-issue.html
then have a close look at your fuse block. If everything looks good, no melting, integrity of all leads good, all connections clean and tight, I would make sure the battery is fully charged and take it to the Corner Parts Store (Advanced AP is a good place), and have your alternator and battery rechecked. Your NB will easily run 20-50 miles on a fully charged Battery, dependent upon what else you have running, e.g. a/c, headlights, etc, even if the Alternator is bad.

I don't spend a lot of time on the Vortex, and don't particularly follow the threads here, I don't check the email that I get p/m notices on very often. I'm always around on "the Org", same user ID. Let me know if I can help furthr.

MORAV


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## tombugby (Nov 27, 2011)

thank you so much! i didnt notice but the fuse block on top of the battery cover is kind of melted and when i opened it up there is some real damage, it looks a lot worse from the inside so i am going to replace the box and the cable to the alternator (it was totally corroded) along with the fuse and then i will try it again. but judging by the damage i will be very surprised if the problem still exists. thank you again for your help.


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## MyOtherRidesAVette (Nov 13, 2010)

You are so welcome. But really I didn't do anything but bring a very common problem to your attention. VW has never come forward and addressed this, so the cause is always speculation. Many of us believe it is caused by substandard wire material. You do need to address potential problems with the alternator/voltage regulator as in many cases this has been pinpointed as the cause. I hope you went to my linked thread and found/find it helpful.

Sorry about the lengthy post, but I try to write for not just you, but anyone who might happen along with a similar problem, and do so assuming the reader has little knowledge of all things electrical, even though for many, much is common knowledge.

Good luck getting your Bug up and running! The referenced thread should pretty much walk you thrugh everything you need to know and do, just a lot of reading and sifting. Come visit us on the Org! If there is anything I can help with, always fastest to p/m me there.

Happy Holidays to you and yours.

Morav


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