I have a charging problem with an '89 e30 ix.... battery light stays
off, voltage while the car is running is a bit less than battery
voltage...

Here's what I've done so far:

Replaced regulator (actually 2 of them)..
bench tested alternator (load & no load)...the guy was an auto electric
guy.. rebuilds alternators.
checked all fuses.. were fine
checked voltage with the car off at the alternator on main + lead and
alternator body.. was close to battery voltage

at that point I thought maybe the alternator wasn't getting voltage on
the blue wire to establish field...so I took the inst. cluster off
and...

tested resistance between blue wire and cluster pin (forgot which
one... came from an apparently misprinted bentley book that has the
rows for the pin numbering wrong)...
tested voltage on various inst. cluster pins according to bentley, all
were fine..
made sure the leads on the ignition switch were good

then thought maybe the inst. cluster wasn't doing whatever it needs to
do to power that blue wire to the alternator, so I replaced it (the
cluster) -- (it was acting flaky anyway... fuel guage was
jumping..etc)..

that didn't help.. (fuel guage looks better though!)

So I'm starting to feel some defeat... does anyone have any other
ideas? Are there any relays that might be broken? Any help would be
appreciated... I'm considering calling Duracell to see if they cell
high capacity, disposable, 12v batterys!

Thanks in advance for any help!

-Aaron

In article <2006092313554016807-altdotautosdotbmw@digitalmafiaorg>,
Aaron Botsis <altdotautosdotbmw@digitalmafia.org> wrote:

Check the warning light bulb and wiring. On many cars this supplies the
field exciting volts. If it's not on with the engine stopped it's the
first thing to check.

--
*Puritanism: The haunting fear that someone, somewhere may be happy.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

On 2006-09-23 14:25:13 -0500, "Dave Plowman (News)"
<dave@davenoise.co.uk> said:



I thought about that... but according to Bentley they put a resister in
parallel with the light in case the bulb goes... could still be the
wiring though I suppose... but that's all in the instrument cluster
replaced...

I'll double check and make sure the bulb is lit before the car is
started and report back...

-Aaron

"Aaron Botsis" <altdotautosdotbmw@digitalmafia.org> wrote in message
news:2006092313554016807-altdotautosdotbmw@digitalmafiaorg...
The voltage at the battery with the engine off should be around 12 volts.
The voltage at the battery with the engine on should be around 14 volts.
If this condition does not exist, your battery will not be charged.

You said that the voltage at the battery with the engine on was less than 12
volts.
This is a clear indication that there is a problem in the charging
circuitry.

A likely cause is a bad regulator, but you said that that you replaced it.
It is most unlikely that two regulators would fail.
Another likely cause is a problem with the alternator, but you said that
someone checked it.

The light goes off when the alternator voltage is higher than battery
voltage. This indicates that the alternator is working fine.
By the way , that light and the resistor you mentioned is the only place in
the instrument cluster which affects your problem.

There is a direct connection between the battery and alternator because the
current is much too high to travel any path but the shortest.
I suppose you did notice that the battery cable is much bigger than those in
the instrument cluster.

Hence, I would check all of the connections and all of the battery to
alternator cables.
Jim

In article <2006092314271775249-nokturnal@maccom>,
Aaron Botsis <nokturnal@mac.com> wrote:

If you've replaced the cluster and the bulb still doesn't work, this
points to a wiring fault. Two blown bulbs are a little too much of a
coincidence. If you have the wiring diagram, you could provide a temporary
ground or +12 volts (whichever it is) to the warning light terminal on the
alternator. If it starts charging you've got it.


--
*Everybody lies, but it doesn't matter since nobody listens*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

"Aaron Botsis" <altdotautosdotbmw@digitalmafia.org> wrote in message
news:2006092313554016807-altdotautosdotbmw@digitalmafiaorg...


Well, I don't know if it is any help but I had a similar problem on my '91 a
while back (Bench tesed fine in all conditions, warning light did not
indicate fault, but yet the battery clearly died when the car was driven),
but a regulator fixed the problem... and I suspect that the brushes were the
only problem with it. All that to say that just 'cuz the alternator checks
out doesn't mean it's good... really makes me wonder why bench test them,
but that's a different question.

On a side note, I now have a regulator with worn out brushes and have been
told that the brushes cannot be replaced in it. Is this true? if not,
where can I get brushes? Thanks

Matt

In article <fklRg.55437$8j3.6754@twister.nyroc.rr.com>,
M Warren <muuarren@hotmail.com> wrote:

There's bench testing and bench testing. One consists of putting the
alternator on a bench and staring at it. The other involves an alternator
test bench which runs it up with an electric motor and checks it properly
- including for maximum output, which is tricky to do without the proper
facilities.

--
*I'm not your type. I'm not inflatable.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:4e6b4ea12adave@davenoise.co.uk...

True, and mine was tested on such a bench. It was computerized and ran
tests specific to the alternator specified. I have seen the times when a
guy puts a belt and a volt meter on it, spins it up and says "yep, she's all
good;" doesn't give me much confidence.

Matt

In article <S1zRg.47891$uH6.4392@twister.nyroc.rr.com>,
M Warren <muuarren@hotmail.com> wrote:

;-)

You might as well do this on the car if that's the limit of the test.

--
*I used up all my sick days so I called in dead

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

On 2006-09-23 20:38:19 -0500, "M Warren" <muuarren@hotmail.com> said:

I heard this too... I think you can replace just the brushes, but it's
a bit of a pain. I think they're riveted on, so you'd have to drill out
the rivets and replace them with screws.

-Aaron