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Discussion Starter #1
I still cannot figure out why my alternator is not charging the battery when engine is running.

Here's the situation:
It has external voltage regulator.
I took out my entire dash panel so all gauges were disconnected. I put it back in and re-connected everything. It's after this that I noticed my car was not charging. (Is there something else I forgot to plug in at the back of the dash that affects the charging system??)

Charging light goes on when I turn key on and stays on when I start the car.
I took the alternator to parts store, they checked it said it was good. It was putting out ~15 volts and ~15 amps.
The voltage regulator that was on there was ~ 2 years old, maybe 3-4k miles on the car since it was new. since I didn't know how to check it, I replaced it with a new one and same situation: no charging.
By the way, what is that cylindrical part with a wire attached that connects to the spade on the bottom of the voltage regulator? Can that cause a problem?

Here is what I find with the V.R.
F termianl - KOEO = 4.45 V; KOER = 4.45 V
#2 terminal - KOEO = 4.45 V; KOER = 5.6 V
#3 terminal - KOEO = 12 V; KOER = 12 V
#4 terminal - KOEO = 4.45 V; KOER = 4.45 V

Also, I checked continuity between F term. on V.R. plug and F terminal plug for back of alt. It is good. I checked the same for #2 terminal on V.R. plug and R terminal plug for back of alt. This also shows good continuity.

I don't know what is wrong.
Please help!
thanks a ton if someone can figure this out!
 

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Discussion Starter #2
I forgot to mention that the V.R. readings noted above were taken while the V.R. plug was plugged into the V.R.

Here is reading with the Key off, plug not plugged into the V.R.
F - 0 V
#2 - 9.75 V
#3 - 12 V
#4 - 0 V

Also, while car is running battery voltage is just over 12 volts, about the same as when not running.
 

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Discussion Starter #3
Please help!
the readings I get are not correct according to other e-mails I've seen.

additional info:
V.R. plug plugged in and key off:

F - 0v
#1 - 0v
#2 - 12v
#3 - 0v
 

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Is the idiot light coming on or is it good? To check that unplug the regulator connector and measure the brown wire to ground with the key on. You should have 12 volts to ground.
If that ok, jumper the brown to blue on the regulator connector (connector removed). With the car running measure the large wire on the back of the alternator to ground. Alternator should go to 16+ volts. This should be a quick test. Don't run the car any longer than is required.
 

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If I were to guess, I would say a bad regulator. You can pull the cover off and check the contact points to see if they are arcing.
 

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Discussion Starter #6
I tried the tests you mentioned. I put the brown wire on the V.R. connector to ground and measured 12 V. Then I connected the blue wire to the brown wire and ran the engine. I measured ~16V at the back of the alternator (the main large lug). What does this tell me?

Also, I tried this: with the V.R. cover off, everything plugged in, engine running, I manually pushed on the top switch to make contact. The system begins charging, but battery voltage goes all over the place, from 13 to 16 volts, and I can tell that the bottom switch doesn't turn on/off/on/off/on/off like it should. It will stay like this until I turn the car off.
 

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Looking at your numbers there seems to be a problem with the wire going to the #2 terminal. That should be 0 with the key off or on until the engine is started. Then, it should go up to 3 or 4 volts or more. This wire is the one that pulls in the small coil in the regulator.

From the numbers you posted there I think you know what should be happening. #2 should be 0 until started and then go to >3.2V (I think) once started. Then #4 should go to 12V. When #2 goes to the same voltage as the F and #4 terminals with the key on and not running it makes me think the regulator isn't grounded. The base must be grounded. Check it by measuring from the base to the -ve terminal of the battery with your volt meter with the key on. If you see voltage get it grounded and try again. It would either have a seperate ground wire with rubber mounts or be grounded by the bolts depending on the year.

When you jumpered the blue and brown wire you tested the alternator and it appears to be working. In your last test, which switch did you push in, the small coil or the large one? I think it would have been the small one but I'm not sure. Still, that also sounds like the regulator ground.

Post back and I'll check back tomorrow night to see what you found.

Peter
 

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Or the core support is floating Peter. There should be a good connection from battery (-) to the right inside fender.
 

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Discussion Starter #9
I have a lot of thanks to dish out! Yes Peter, the problem turned out to be that the voltage regulator was not grounded. There was 4 volts floating on the base. The ground wire from the base was not hooked up correctly to the core support. I connected properly and it works great! You don't know how happy I was to see that work. A lot of times the fix is simple, but the troubleshooting isn't. Thanks again for all the feedback I received.
 

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Good to hear it's fixed.

Originally posted by John_Muha:
Or the core support is floating Peter. There should be a good connection from battery (-) to the right inside fender.
That's why I recommend measuring from the regulator base right to the -ve battery terminal. It checks all the grounding.

Peter
 

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Originally posted by Peter F.:
Good to hear it's fixed.

</font><blockquote>quote:</font><hr />Originally posted by John_Muha:
Or the core support is floating Peter. There should be a good connection from battery (-) to the right inside fender.
That's why I recommend measuring from the regulator base right to the -ve battery terminal. It checks all the grounding.

Peter
</font>[/QUOTE]Missed that. Guess not reading everything but if everyone would take the time and check things like this guy did, they would often save a whole lotta cash. Most "Electrical Specialists" here just replace everything on your dime and go from there.
 
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