What is this? - BMW Forum

drz · 01-17-2006, 09:24 PM

I think my battery has gone kaput. This morning when I was heading out to work, I noticed the battery indicator on the instrument cluster illuminate intermitently, especially at low revs. I figured the battery was going bad, but I needed to get to work. I kept the revs over 1000, even while stopped. Tonight, as I was coming home, I noticed my dash illumination was getting dimmer. By the time I got home, the ASC light, the ABS light, and the Airbag light were all illuminated permanently.

Sounds like battery problem?

Ljk619 · 01-17-2006, 09:32 PM

You might want to check the alternator as well, cause if it's not charging enough and you change the battery, the new battery will run into the same problem.

94BMW325i · 01-17-2006, 10:02 PM

you checked your terminals on the battery, and everything just in case, make sure nothings loose?

BImmerN2B · 01-17-2006, 10:02 PM

I second the alternator and who know if with it also the voltage regulator

Furious · 01-17-2006, 11:20 PM

its gonna be the alternator, not often is it the Voltage regulator but cant rule that component out.

Cruzin 323is · 01-18-2006, 12:34 AM

ok, well in the morning see if u get a rough start... and we'll go from there...

a buddy of mine has a jetta (01) and this is what happeend when an o2 sensor went bad.. he had a very rough start.. and had a problem holding idle.. then stalling unless keeping rpm high...

he also had traction control, airbag, and battery light on... and 02 sensor fixed it...

if check engine light on?

Furious · 01-18-2006, 02:43 AM

the reason that the other lights come on , is because when the alternator is failing, all the secondary systems like abs, srs and dsc lights go on because they arent receiving proper voltage.. i had the exact same thing happen to me when my alternator started to go.

Ivan · 01-18-2006, 02:44 AM

i had the same problem, it turned out to be the alternator.

drz · 01-18-2006, 09:01 AM

Well, I'll look into it. I will probably take out the alternator and have it check out soemwhere. I'll go from there.

Oh, and the Check ENgine Light is NOT on, so I will rule out the o2 sensor for now. My light did come on about eight monsth ago, and the code pointed to the o2 sensors, but the light went away and never came back.

drz · 01-22-2006, 06:44 PM

Okay, problem still there. Yesterday I took out the alternator and had them test it for me at AutoZone. The alternator passed the test twice. I then took my battery and they said it was a good battery, in need of a charge. SO they charged it for me for about 30 minutes. Checking the fusebox, I noticed that the 30 amp fuse for the auxiliary fan was out. My aux. fan has not been working for a while, so I assumed maybe the motor is seized, but still trying to draw current (locked rotor current is very high) from the charging system.

I was heading back home tonight and the problem resurfaced. I was getting the battery charge indicator to illuminate intermitently, this time it is very random. It used to come on with low rpms, but tonight it just came on a different times. I will check the fusebox again, and also some connections, but I am afraid I will have to take it in to a mechanic to have him track the problem. I know that car electrical can be a pain to diagnose, but I am getting a little irritated now.

Any further input will be gratedly appreciated.

SpeedInfusion · 01-22-2006, 07:14 PM

have u checked ur main ground wire terminal? where the main ground wire connects to the chasis, sometimes a loose connection or formation of that white stuff on the terminal causes this to happen...does ur car stutter when u press the gas when this happens?

drz · 01-22-2006, 08:15 PM

Car doesn't stutter. Where is the ground wire connectio?

SpeedInfusion · 01-22-2006, 08:44 PM

Quote:

Originally Posted by drz

Car doesn't stutter. Where is the ground wire connectio?

i think its in the engine bay.....ill double check..

drz · 02-10-2006, 02:09 AM

After talking about my problem with a friend, we came to the conclusion that an alternator can pass the bench test at Autozone (or elsewhere) even if the voltage regulator is bad. My friend explained that most of the time, the voltage regulator fails once the alternator has warmed up. Since the alternator is cold when one takes it in to be tested, voltage regulator problems can go undetected. Furthermore, this was consistent with my problems, because I only noticed weird things after I had driven for a short while.

I ordered a new alternator, which I put in today. So far I have had no trouble in spite of driving around plenty -- in the dark and all. I ordered a whole alternator instead of just the voltage regulator because the alternator seems to be the original, which has over 185,000 miles on it. If the voltage regulator failed, the rest was very likely to follow soon thereafter. So instead of paying $60 now and $200 later, I just paid $200 now.

I will come back if any problems reappear.