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Discussion Starter · #1 ·
My new alternator + voltage regulator is definitely not charging. 12.03 volts at the battery at idle, less when I hit the gas. Same value at alternator. Revved it up to 2K-3K RPM several times, no change.
Blue wire shows ~9 volts at the alternator, but over 11 at the connector before the new wire starts. Battery light still isn't coming on, though.
Can anyone measure, or do you know offhand, the proper voltage for that wire at the alternator? Do you know where that power comes from and what it takes to complete that circuit? I'm going to exorcise this demon tomorrow come hell or high water.
Research on this problem, and a previous post, have been less than helpful so far.
Thanks for your assistance.
 

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Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

even when i UNPLUGGED the blue wire i got 14.5V at the alternator (Transpo set to that).
didn't seem to matter if it was plugged in or not , the voltage charged the same at 1100rpms (my idle choice)
little bit less at the battery i suspect old wiring might have to do with that
 

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Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

you're actually getting voltage to that blue wire?.. heheh. mine never did. I guess the connection was broken somewhere a long time ago.
 

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Discussion Starter · #4 ·
Re: Can someone measure the voltage on your blue alternator wire? (jwatts)

Hmm. So how is it your systems are charging and mine isn't?
Or am I testing something the wrong way?
 

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Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

Is this the same post where your battery LED did not come on at all? That LED is required to "excite" the field wiindings in your alternator. Your output voltage at the alternator will never reach proper voltage without that LED. This is a common problem with lots of A2s. Good luck.
 

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Discussion Starter · #6 ·
Re: Can someone measure the voltage on your blue alternator wire? (finzup)

You are correct; this is the same problem. The answers to the previous post were not entirely helpful so I decided to try a new one.
The blue wire appears to be good all the way up to the cluster, and the fuses are fine. I currently have the cluster apart and I'm trying to test the printed circuit now. So far the diodes and resistors look okay, or at least they're giving consistent resistance values, so I'm going to test the LED next.
After that I'm going to set the car ablaze if I don't find the problem.

Thanks for the replies.
 

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Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

You must have missed the part where i said . I REMOVED THE BLUE WIRE from the alternator, and it didn't make a damn bit of difference. 14.5V volt (transpo).
Excited or not, the power output was there, voltmeter in cabin verified..
What do you get without your "excitement"?
 

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Re: Can someone measure the voltage on your blue alternator wire? (mrkrad)

with my non-excited blue, the output at the cig. lighter is 13.0-13.2V,, which is about .5V lower than at the battery. I have to rev to about 3k once to get it to start charging, though.
doh, early morining typo corrected.... my blue wire never had voltage

Modified by jwatts at 1:54 PM 6-30-2003


Modified by jwatts at 1:55 PM 6-30-2003
 

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Re: Can someone measure the voltage on your blue alternator wire? (jwatts)

no kidding? Did you put the transpo in? Blackie was pegging 14.5V at the cig lighter with that thang turned up.
 

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Re: Can someone measure the voltage on your blue alternator wire? (mrkrad)

just because the alternator is new doesnt mean its good ...
 

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Discussion Starter · #11 ·
Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

After screwing with it all morning I'm quitting for the day. I redid several ugly splices in various ground wires that I found, courtesy of the retard who used to own my car. No changes. The blue wire is good all the way up to the cluster. The ground wire from the cluster is good also; I found negligible resistance between it and body ground. All the gauges are working properly, though I did accidentally break the tach needle.

Resistors and diodes in the cluster are all good. LED is good. However, both (+) and (-) leads to the LED are getting voltage with the ignition on - this is with or without the LED actually in the socket to complete the circuit. The oil pressure and seat belt lights are no longer functioning either.
So it would seem that I've got a short somewhere in the cluster PCB but I haven't found it yet. I have sourced another cluster and I should be able to get it in tomorrow.
I've also been looking through the wiring diagrams in the Bentley and I can't see where, on that blue wire exciter wire circuit, is the ignition key. Obviously the ignition is part of that circuit since that light only goes on when the key is turned. Ideas?
Lastly, I'm going to take that alternator to have it tested, even though it came with a computer printout of its test run at the remanufacturer.
This is absurd. I'm going to have some lunch, and then some beer, and forget about it until tomorrow.
 

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Discussion Starter · #12 ·
Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

Oh, yeah, one other thing. The Bentley depicts a "condenser" attached to the alternator and plugged into it from the outside. In the picture it's just a little box screwed down to the outside of the alternator and plugged into a post also on the outside. My alternator doesn't have this; just an empty post.
Help? I can take pictures if you want.
Also, I found this article which you may find interesting. Look under "What's the charge?" and "Feeling blue."
http://www.tomorrowstechnician.com/tt/tt30273.htm



Modified by autopimp at 1:56 PM 6-30-2003
 

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Discussion Starter · #13 ·
Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

Update, in case anyone cares: it appears the short is in the alternator itself. I can find no faults in any of the related wiring; the new cluster PCB I tested behaved in exactly the same manner as the old one; and when I disconnected the blue wire from the alternator and shorted it directly to ground, guess what - that battery light came on.
I tried EVERYTHING. I traced wires, tested voltages, traced the circuit all the way across the PCB and each component thereupon; I even ran a wire from the battery directly to the alternator (where the blue wire connects) to try to manually stimulate (heh) it into charging, and nothing - nothing - nothing. Not to mention all the ground wires I found, fixed, tightened, etc.
I'm taking the alternator to its place of purchase to be tested right now. Results to be posted in an hour or so.
By the way, if you have a Bentley, turn to 27.11 and look at the drawing on the lower right (27-603). That is the "suppression condenser" I mentioned earlier, that I don't have. What the hell is it, and could that be the reason my alternator doesn't work? Anyone?



Modified by autopimp at 11:03 AM 7-1-2003
 

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Discussion Starter · #14 ·
Alternator was bad - only putting out 2 volts on the Autozone test bench. Sigh. Another one is on order.
 

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Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

well if its like advanced auto its "lifetime warranty" so at least this will be the last one

get a transpo VR while you're mucking around.
 

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Discussion Starter · #16 ·
Re: Can someone measure the voltage on your blue alternator wire? (mrkrad)

Yes, about that...what's the easiest way to get a hold of a Transpo?
 

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Discussion Starter · #17 ·
Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

The End.
After having run a pretty new blue exciter wire, re-done several ground connections and splices, broken my tach needle, lost all three of my instrument panel light bulbs
and learned more than I ever wanted to know about my instrument cluster and charging system circuitry, I have come to the end of this particular struggle.
The problem was the alternator. Nothing more. My second new alternator is in place, with a freshly painted fan and pulley, and putting out 14.35 volts at 1200 RPM (or so). Voltage across the battery is 14.05 under same conditions. Is a .3 volt drop enough to justify new battery / starter cables? I think it's okay for now. Hell, I don't even want a Transpo anymore.
Moral: When you're getting a new or remanufactured alternator, have it tested anyway before installing. And don't be hesitant to consider it as a failure point, no matter how new it is, when you're troubleshooting.

The car feels great now. Once I source a new needle and light bulbs I'll be happy again. Now to the next item on the list: the passenger side window that won't roll up. Wish me luck folks...and thanks for tuning in.
 

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Re: Can someone measure the voltage on your blue alternator wire? (mrkrad)

Quote, originally posted by mrkrad »
You must have missed the part where i said . I REMOVED THE BLUE WIRE from the alternator, and it didn't make a damn bit of difference. 14.5V volt (transpo).
Excited or not, the power output was there, voltmeter in cabin verified..
What do you get without your "excitement"?

But you did not do a verifiable test. Anyone can do that. You must first unplug the blue wire, start your car and then see what the voltage is, then plug it in and see if there is a difference. By doing it in reverse, it is already going to have excited the alternator so it no longer needs to be connected.
 

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Re: Can someone measure the voltage on your blue alternator wire? (autopimp)

i just rev it past 3500 or 3000 and my Alt kicks in after that
 

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Re: Can someone measure the voltage on your blue alternator wire? (wolf rocco)

my test always was... put an impact on the alt let it slowly accelerate so it will freewheel at a few thou rpm... have something on it that would take a load and put 12v power to the blue excitor wire connection on the alt... if everything is good the impact will instantly start hammerin if not it will keep on freewheelin

i had to come back and post that it was my 666 post... hehehe time to go drive my 666 corrado now


Modified by yellerrado at 1:21 AM 10-13-2004
 
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