[Vwdiesel] 89 Jetta na charging system
val at mongo.mongobird.com
Mon Jul 25 16:27:56 PDT 2011
In my experience, this is usually a sign of worn brushes. Pull them
and check their length. On the Bosch alternator, they are easy to
(This applies to the IDI engines...the alternator on the TDIs have different
> I had a similar experience years ago with my 78 Rabbit.
> The battery light never really "came on", but sometimes, in the right light,
> if you looked carefully you could see a dull red glow (much easier to see in
> the dark of course).
> Who knows how long it had been doing this before I noticed it, but when I
> did notice it (on my way home from college for the weekend of course... with
> a 5 hour drive through God-forsaken-BF-nowhere in between), I stopped into
> one of those Battery Factory type places.
> They put the load tester on the car, pulled a good load and pronounced the
> alternator "fine".
> I continued to tootle around all weekend, aware of the coming and going of
> the light, but trusting the "professional" and assuming it was "fine".
> My last night in town, the alternator finally gave up on the
> "on-again-off-again" and just went with the off. I was a good 30-40 minutes
> from my folks house(where I was planning to sleep) but relatively close to
> my buddy's place, so I headed there. As I drove, I could see the headlight
> (single - in a happy coincidence, one of them had burned out, saving
> precious juice!) and dash lights getting dimmer and dimmer. When I was
> about a mile away, the car started to misfire at higher RPMs, I assume
> because the electric fuel pump could no longer supply enough gas.
> I ended up crashing at my buddy's house and changing the alternator in the
> morning.. thankfully he had the deep socket necessary to get the alt pulley
> Long story short... it's a sign of impending failure. Just change the
> alternator before you end up stranded somewhere. :)
> On Mon, Jul 25, 2011 at 3:42 PM, Doyt W. Echelberger <
> doyt at buckeye-express.com> wrote:
> > When my car is running, is there EVER a time that the battery dash light
> > should come on red, other than the brief interval when I first switch on the
> > ignition ? (If this is a duplicate post, I apologize.)
> > The red dash light for the battery on this 89 Jetta diesel has glowed dull
> > red at times and not at other times. The dim red light on the dash called my
> > attention to this by coming on during a drive around town recently. OK, red
> > dash lights are put there for a reason by the designers so I popped the hood
> > and with the engine running put the volt meter across the battery posts. It
> > read a steady 12.8 volts.
> > Conclusion: The alternator wasn't charging the battery at that time, and
> > 12.8 volts didn't trigger the voltage regulator to fire up the alternator
> > fields.
> > So, I made an appointment to have the charging system checked. I take the
> > car in tomorrow.
> > This morning, I started the engine and there was NO RED BATTERY LIGHT
> > flickering on the dash. I popped the hood and put the voltmeter across the
> > battery terminals and read 14.8 volts. I turned off the engine and the same
> > voltmeter read 12.8 volts. Clearly, the alternator has started working.
> > I then drove the car for half an hour. The battery light stayed off, off
> > at the end of the trip I again measured the voltage across the battery
> > terminals while the car was running. 13.7 volts.
> > I am puzzled by this behavior. Will my mechanic be able to identify the
> > cause of this unreliable feature and fix it?
> > I have a spare alternator from my old 1985 Jetta TD, and it worked OK a few
> > years ago when the TD was running.
> > I think I'll put it in the trunk when I take the car in, and mention it to
> > the mechanic.
> > But right now, he doesn't have anything to fix. The alternator seems to
> > work just fine. Does he have miracle tools that tell him what made my
> > battery light come on one day, and then stay off the next?
> > Doyt
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